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Sample records for clam ruditapes philippinarum

  1. Metabolic responses of clams, Ruditapes decussatus and Ruditapes philippinarum, to short-term exposure to lead and zinc.

    Science.gov (United States)

    Aru, Violetta; Sarais, Giorgia; Savorani, Francesco; Engelsen, Søren Balling; Cesare Marincola, Flaminia

    2016-06-15

    This study investigated the effects of 48h heavy metal exposure upon the metabolic profiles of Ruditapes decussatus and Ruditapes philippinarum using (1)H NMR metabolomics. Both species were exposed to increasing concentrations of lead nitrate (10, 40, 60 and 100μg/L) and zinc chloride (20, 50, 100 and 150μg/L), under laboratory conditions. ICP-OES analysis was further performed on the clams' samples in order to verify the occurrence of heavy metal bioaccumulation. With respect to the controls, the metabolic profiles of treated R. decussatus exhibited higher levels of organic osmolytes and lower contents of free amino acids. An opposite behavior was shown by R. philippinarum. In terms of heavy metal, the exposure effects were more evident in the case of Pb rather than Zn. These findings show that NMR-based metabolomics has the required sensitivity and specificity for the identification of metabolites that can act as sensitive indicators of contaminant-induced stress.

  2. Use of antioxidant enzymes of clam Ruditapes philippinarum as biomarker to polycyclic aromatic hydrocarbon pollution

    Science.gov (United States)

    Zhu, Lin; Tang, Xuexi; Wang, Ying; Sui, Yadong; Xiao, Hui

    2016-03-01

    The typical organic pollutant polycyclic aromatic hydrocarbon (PAH) anthracene was selected as a contaminant to investigate its effects on the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in the clam Ruditapes philippinarum. The results show that SOD, CAT and GSH-Px had diff erent induction and inhibition reactions to anthracene stress, and that three diff erent organs in R. philippinarum (visceral mass, muscle tissue and mantle) had diff erent sensitivities to anthracene stress. This study suggest that SOD activities of the visceral mass, CAT activitities of the mantle and the visceral mass, and GSH-Px activity of the muscle tissue could be used as sensitive indicators of anthracene stress in R. philippinarum.

  3. Assessment of immune parameters of manila clam Ruditapes philippinarum in different physiological conditions using flow cytometry

    Science.gov (United States)

    Park, Kyung-Il; Donaghy, Ludovic; Kang, Hyun-Sil; Hong, Hyun-Ki; Kim, Young-Ok; Choi, Kwang-Sik

    2012-03-01

    Cellular and humoral immune parameters are often used as biomarkers to trace environmental and physiological stresses in marine bivalves. In this study, we compared various immune parameters of Manila clams ( Ruditapes philippinarum) under normal conditions and under a high level of desiccation, using flow cytometry. The immune parameters analyzed included, total hemocyte count, hemocyte mortality, hemocyte DNA damage, reactive oxygen species (ROS) production, and phagocytosis activity. Total hemocyte count, hemocyte DNA damage, and hemocyte mortality were significantly elevated among clams under high desiccation stress, while phagocytosis activity and spontaneous ROS production were significantly lower compared to those parameters of the control clams ( pimmune parameters analyzed in this study well reflect the physiological status of clams.

  4. Infection of Manila clams Ruditapes philippinarum from Galicia (NW Spain) with a Mikrocytos-like parasite.

    Science.gov (United States)

    Ramilo, Andrea; Iglesias, David; Abollo, Elvira; González, Mar; Darriba, Susana; Villalba, Antonio

    2014-07-24

    The name 'microcells' is frequently used to refer to small-sized unicellular stages of molluscan parasites of the genera Bonamia (Rhizaria, Haplosporidia) and Mikrocytos (Rhizaria). Histological examination of Manila clams Ruditapes philippinarum revealed microcells in the connective tissue of adductor muscle, foot, mantle, gills, siphon and visceral mass. The clams had been collected from 4 beds on the coast of Galicia, Spain. The prevalence of these microcells ranged from 73 to 93% in surface clams and from 3 to 33% in buried clams. However, the detection of brown ring disease signs in clams from every bed prevented us from making the assumption that the microcells alone were responsible for clam mortality. PCR assays using primer pairs designed to detect Bonamia spp. and haplosporidians gave negative results, whereas positive results were obtained with primers for the genus Mikrocytos. A consensus sequence of 1670 bp of the ribosomal gene complex of the microcells was obtained. It contained a section of the 18S region, the whole first internal transcribed spacer, the 5.8S region, the second internal transcribed spacer and a section of the 28S region. Comparison of this sequence with those of M. mackini infecting Crassostrea gigas and Mikrocytos sp. infecting Ostrea edulis showed that the microcells of Galician clams were the most divergent among the compared parasites. This is the first report of a Mikrocytos-like parasite infecting Manila clams. Care must be taken to avoid the spread of this parasite through Manila clam transfers.

  5. Accumulation of petroleum hydrocarbons and heavy metals in clams (Ruditapes philippinarum) in Jiaozhou Bay, China

    Institute of Scientific and Technical Information of China (English)

    MA Haiqing; SONG Qian; WANG Xuchen

    2009-01-01

    Accumulation and distributions of aliphatic and polyaromatic hydrocarbons (PAHs) and heavy metals were measured in tissues of the clam Ruditapes philippinarum collected from 5 sites in Jiaozhou Bay, Qingdao, China. The concentrations of total aliphatic hydrocarbon and PAHs ranged from 570 to 2 574 ng/gdw (gram dry weight) and from 276 to 939 ng/gdw, in the most and least polluted sites, respectively. The bio-accumulation of hydrocarbons and PAHs in the clams appeared to be selective. Aliphatic hydrocarbons were predominantly represented by short chain (clams was probably related to the physiological and bio-kinetic processes that were energetically favorable for uptake of compounds with fewer rings. Accumulation of the metals Cd, Cu, Zn, Pb, Cr, Hg, and As in the clam tissues also showed high variability, ranging from 0.043 to 87μg/gdw. Among the 7 detected metals, Zn, Cd, Cu, and As had a particularly high potential of accumulation in R. philippinarum. In general, a positive correlation was found between the tissue concentrations and sediment concentrations of hydrocarbons and of some metals. Our study suggests that moderate contamination with polyaromatic hydrocarbons, and low to moderate contamination with metals, currently exists for clam R. philippinarum in Jiaozhou Bay, in comparison with other regional studies. A long-term monitoring program is certainly needed for assessment of the potential ecological influence and toxicity of these contaminants of R. philippinarum in Jiaozhou Bay.

  6. Distribution of butyltins (TBT, DBT, MBT) in sediments of Gulf of Cadiz (Spain) and its bioaccumulation in the clam Ruditapes philippinarum

    Digital Repository Service at National Institute of Oceanography (India)

    Garg, A; Anton-Martin, R.; Garcia-Luque, E.; Riba, I.; DelValls, T.A

    , suggesting that these sediments are polluted with butyltin compounds. The clam Ruditapes philippinarum was used for studying bioaccumulation of butyltins by exposing them to contaminated sediments from the Gulf of Cadiz over a period of 28 days under...

  7. Assessment of clam ruditapes philippinarum as Heavy metal bioindicators using NMR-based metabolomics

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaoli; Zhang, Linbao; You, Liping [Key Laboratory of Coastal Zone Environment Processes, CAS, Shandong Provincial Key Laboratory of Coastal Zone Environment Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai (China); The Graduate School of Chinese Academy of Sciences, Beijing (China); Yu, Junbao; Cong, Ming; Wang, Qing; Li, Fei; Li, Lianzhen; Zhao, Jianmin; Li, Chenghua; Wu, Huifeng [Key Laboratory of Coastal Zone Environment Processes, CAS, Shandong Provincial Key Laboratory of Coastal Zone Environment Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai (China)

    2011-08-15

    There are mainly distributed three pedigrees (White, Liangdao Red, and Zebra) of Manila clam Ruditapes philippinarum in Yantai population along the Bohai marine and coast. However, the biological differences to environmental stressors have been ignored in toxicology studies, which could lead to the distortion of biological interpretations of toxicological effects induced by environmental contaminants. In this study, we applied a system biology approach, metabolomics to compare the metabolic profiles in digestive gland from three pedigrees of clam and characterize and compare the metabolic responses induced by mercury in clam digestive gland tissues to determine a sensitive pedigree of clam as a preferable bioindicator for metal pollution monitoring and toxicology research. The most abundant metabolites, respectively, included branched-chain amino acids, alanine, and arginine in White samples, glutamate, dimethylglycine, and glycine in Zebra clams and acetylcholine, betaine, glucose, and glycogen in Liangdao Red clams. After 48 h exposure of 20 {mu}g L{sup -1} Hg{sup 2+}, the metabolic profiles from the three pedigrees of clams showed differentially significant changes in alanine, glutamate, succinate, taurine, hypotaurine, glycine, arginine, glucose, etc. Our findings indicate the toxicological effects of mercury exposure in Manila clams including the neurotoxicity, disturbances in energetic metabolisms and osmoregulation in the digestive glands and suggest that Liangdao Red pedigree of clam could be a preferable bioindicator for the metal pollution monitoring based on the more sensitive classes of metabolic changes from digestive glands compared with other two (White and Zebra) pedigrees of clams. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Transcriptomic responses to low temperature stress in the Manila clam, Ruditapes philippinarum.

    Science.gov (United States)

    Nie, Hongtao; Jiang, Liwen; Huo, Zhongming; Liu, Lianhui; Yang, Feng; Yan, Xiwu

    2016-08-01

    The Manila clam, Ruditapes philippinarum, is an economically important shellfish in marine aquaculture, with a broad thermal tolerance. The ability to cope with cold stress is quite important for the survival of aquatic species under natural conditions. A cold-tolerant clam that can survive the winter at temperatures below 0 °C might extend our understanding of the mechanisms underlying the response to cold stress. In this study, the transcriptional response of the Manila clam to cold stress (-1 °C) was characterized using RNA sequencing. The transcriptomes of a cold-treatment (O) group of clams, which survived under cold stress, and the control group (OC2), which was not subjected to cold stress, were sequenced with the Illumina HiSeq platform. In all, 148,593 unigenes were generated. Compared with the unigene expression profile of the control group, 1760 unigenes were up regulated and 2147 unigenes were down regulated in the O group. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses revealed that signal transduction, mitochondrial metabolism, cellular component organization or biogenesis, and energy production processes were the most highly enriched pathways among the genes that were differentially expressed under cold stress. All these pathways could be assigned to the following biological functions in the cold-tolerant Manila clam: signal response to cold stress, antioxidant response, cell proliferation, and energy production.

  9. Is metal contamination responsible for increasing aneuploidy levels in the Manila clam Ruditapes philippinarum?

    KAUST Repository

    Piló, D.

    2016-11-03

    The present study assessed the metal genotoxicity potential at chromosome-level in the bivalve Ruditapes philippinarum collected along different areas of the Tagus estuary. Higher levels of aneuploidy on gill cells were detected at the most sediment contaminated area both in May (31.7%) and October (36.0%) when compared to a less contaminated area over the same periods (20.3% and 29.0% respectively). Interestingly, metal bioaccumulation in gills was higher in the specimens collected at the least contaminated area with the exception of Pb. Indeed, the multivariate analysis revealed a stronger relation between aneuploidy and sediment contamination than between aneuploidy and the bioaccumulation of the metals. The temporal and spatial inconsistency found for the bioaccumulation of metals in R. philippinarum and the positive correlation between sediment contamination and aneuploidy at the most contaminated area suggest that these chromosome-level effects might be due to chronic metal contamination occurring in the Tagus estuary, rather than a direct result of the temporal variation of bioavailable contaminants. The vertical transmission phenomenon of bivalve aneuploidy levels may then be perpetuating those levels on clams from the most contaminated area. The present results shed light about the effect of metal toxicity at the chromosome-level in species inhabiting chronic contaminated areas and highlight the use of aneuploidy as an effective tool to identify persistent contamination in worldwide transitional waters.

  10. Gene transcription and biomarker responses in the clam Ruditapes philippinarum after exposure to ibuprofen

    Energy Technology Data Exchange (ETDEWEB)

    Milan, Massimo; Pauletto, Marianna; Patarnello, Tomaso; Bargelloni, Luca [Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell' Universita 16, Legnaro (Padova) (Italy); Marin, Maria Gabriella [Department of Biology, University of Padova, Via Ugo Bassi 58/B, 35131 Padova (Italy); Matozzo, Valerio, E-mail: matozzo@bio.unipd.it [Department of Biology, University of Padova, Via Ugo Bassi 58/B, 35131 Padova (Italy)

    2013-01-15

    Pharmaceuticals are a class of emerging environmental contaminants that continuously enter aquatic environments. Presently, little information is available about the effects of these substances on non-target organisms, such as bivalves. We investigated the effects of ibuprofen (IBU) on the clam Ruditapes philippinarum. Clams were exposed for 1, 3, 5 and 7 days to 0, 100 and 1000 {mu}g IBU/L, and established biomarker responses (haemolymph lysozyme, gill acetylcholinesterase and digestive gland superoxide dismutase activities) as well as digestive gland transcriptome were evaluated. A two-way ANOVA revealed significant effects of both 'IBU concentration' and 'exposure duration' on biomarker responses. Overall, the enzyme activities were generally lower in IBU-exposed clams than in controls. Although limited knowledge of the mollusc transcriptome makes it difficult to interpret the effects of IBU on clams, the gene transcription analysis using DNA microarrays enabled the identification of the putative molecular mode of action of the IBU. The functional analysis of differentially transcribed genes suggests that IBU can interfere with various signalling pathways in clams, such as arachidonic acid metabolism, apoptosis, peroxisomal proliferator-activated receptors, and nuclear factor-kappa B. In addition, several genes involved in the metabolism of xenobiotics (e.g., glutathione S-transferase, sulfotransferase, cytochrome P450) were also found to be significantly affected by IBU exposure. In summary, the integrated approach of gene transcription analysis and biomarker responses facilitated the elucidation of the putative mechanisms of action of IBU in non-target species.

  11. Lipid characteristics of a seep clam, Mesolinga soliditesta: Comparison with those of two coastal clams, Meretrix lamarckii and Ruditapes philippinarum

    Science.gov (United States)

    Saito, Hiroaki; Murata, Masakazu; Hashimoto, Jun

    2014-12-01

    The lipids and fatty acids of two coastal clams, Meretrix lamarckii and Ruditapes philippinarum, collected at 5 and 1 m of depth, and a seep clam, Mesolinga soliditesta, collected at 331 m of depth, were examined to assess their lipid physiology and trophic relationship with their diets. The major fatty acids of lipids in Mer. lamarckii and R. philippinarum were 14:0, 16:0, 18:0, 16:1n-7, 18:1n-9, 18:1n-7, 20:4n-6, 20:5n-3, and 22:6n-3, while those of Mes. soliditesta were 16:0, 18:0, 16:1n-7, 18:1n-7, 20:1n-7, 20:1n-13, 20:2n-7, 15 (Δ5,13-20:2), and 22:2n-7,15 (Δ7,15-22:2). The major polyunsaturated fatty acids (PUFAs) in the Mer. lamarckii and R. philippinarum lipids consisted of various n-3 and n-6 long-chain (LC) PUFAs, such as 20:4n-6, 22:4n-6, 20:5n-3, 22:5n-3, and 22:6n-3, while those in Mes. soliditesta muscle and viscera included various n-4 family PUFAs (18:3n-7, 18:4n-4, 20:2n-7, and 20:3n-7) with limited kinds of n-3 and n-6 PUFAs (20:4n-6 and 20:5n-3). These findings indicate that, like other common shallow-water clams, Mer. lamarckii and R. philippinarum ingest phytoplanktonic n-3 and n-6 LC-PUFAs, whereas Mes. soliditesta utilizes limited kinds of n-3 and n-6 LC-PUFAs. In contrast to the other two bivalves species, Mes. soliditesta yielded various n-4 and n-7 (n-4/n-7) PUFAs, which were assimilated from the chemosynthetic symbionts. The high diversity of PUFAs contained in the Mes. soliditesta lipids (n-3, n-4 family, and n-6 PUFAs) suggests that this species mixotrophically utilized both photosynthetic products and vent chemosynthetic nutrition derived from geothermal energy.

  12. Inbreeding depression on growth and survival of full-sib family of Manila clam ( Ruditapes philippinarum)

    Science.gov (United States)

    Huo, Zhongming; Li, Na; Zhang, Xuekai; Li, Ying; Yan, Xiwu; Yang, Feng

    2017-02-01

    In present study, the inbreeding depression ( ID) of growth and survival of Manila clam (Ruditapes philippinarum) was investigated at larval and juvenile stages. Nine inbred families ( A 2, B 2, C 2, D 2, E 2, F 2, G 2, H 2 and I 2) were established by mating within nine full-sib families with expected inbreeding coefficient of 0.25. Inbred families showed significant differences in shell length and hatching rate of D-larvae (straight-hinged larvae). The larvae of the nine inbred families grew slower than those of control group ( CG), and their ID value ranged from 0.81% ± 6.09% to 16.10% ± 1.49%. The ID value of larval survival rate varied between 27.47% ± 9.36% and 70.50% ± 13.66%. The ID was also detected for juvenile growth in A 2, B 2, C 2, and D 2, which ranged from 4.60 ± 2.21 to 17.71 ± 7.73. The A 2 family maintained the highest juvenile survival rate, whereas the other inbred families exhibited ID values varying between 62.79% ± 4.54% and 96.14% ± 0.87%. The linear relationship of estimated ID between growth and survival was negatively correlated ( R = -0.434, P < 0.05). The results of this study suggested that the ID of growth was common at the larval stage but was less prevalent at juvenile stage. In contrast, the ID of survival increased from larval to juvenile stage. A better understanding of the effect of inbreeding may aid to selective breeding of Manila clam.

  13. Transcriptomics of in vitro immune-stimulated hemocytes from the Manila clam Ruditapes philippinarum using high-throughput sequencing.

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    Rebeca Moreira

    Full Text Available BACKGROUND: The Manila clam (Ruditapes philippinarum is a worldwide cultured bivalve species with important commercial value. Diseases affecting this species can result in large economic losses. Because knowledge of the molecular mechanisms of the immune response in bivalves, especially clams, is scarce and fragmentary, we sequenced RNA from immune-stimulated R. philippinarum hemocytes by 454-pyrosequencing to identify genes involved in their immune defense against infectious diseases. METHODOLOGY AND PRINCIPAL FINDINGS: High-throughput deep sequencing of R. philippinarum using 454 pyrosequencing technology yielded 974,976 high-quality reads with an average read length of 250 bp. The reads were assembled into 51,265 contigs and the 44.7% of the translated nucleotide sequences into protein were annotated successfully. The 35 most frequently found contigs included a large number of immune-related genes, and a more detailed analysis showed the presence of putative members of several immune pathways and processes like the apoptosis, the toll like signaling pathway and the complement cascade. We have found sequences from molecules never described in bivalves before, especially in the complement pathway where almost all the components are present. CONCLUSIONS: This study represents the first transcriptome analysis using 454-pyrosequencing conducted on R. philippinarum focused on its immune system. Our results will provide a rich source of data to discover and identify new genes, which will serve as a basis for microarray construction and the study of gene expression as well as for the identification of genetic markers. The discovery of new immune sequences was very productive and resulted in a large variety of contigs that may play a role in the defense mechanisms of Ruditapes philippinarum.

  14. Identification of Perkinsus-like parasite in Manila clam, Ruditapes philippinarum using DNA molecular marker at ITS region

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Genomic DNA was extracted from hypnospores of Perkinsus-like parasite of Manila clam Ruditapes philippinarum collected at the fishing grounds in Huanghai Sea coast Shicheng Island and East China Sea coast Ningbo, China. The internal transcribed spacer(ITS)in rDNA was PCR-amplified, cloned, sequenced, and compared with that of five Perkinsus species in GenBank. The fragment amplified from DNA of parasite of either Shicheng Island or Ningbo contained 649 bp, including partial ssrRNA(51 bp) and ITS(+5.8 S)(598 bp) regions. The ITS(+5.8S) sequences of Perkinsus-like parasite of both Shicheng Island and Ningbo were all 99% identical to those ofPerkinsus atlanticus,and were not more than 95% identical to those of other four Perkinsus species including P. marinus, P.andrewsi, P. qugwadi and P. medierraneus.The ITS (+5.8S) sequence of Perkinsus-like parasite of Shicheng Island was 99% identical to that of Ningbo. These facts about nucleotide sequences suggested that the Perkinsus-like parasite in Manila clam, Ruditapes philippinarum collected from either the Huanghai Sea coast or the East China Sea coast was P. atlanticus, and might reflect P. atlanticus strains of distinct geographic distribution.

  15. NMR-Based Metabolomic Investigations on the Differential Responses in Adductor Muscles from Two Pedigrees of Manila Clam Ruditapes philippinarum to Cadmium and Zinc

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    Junbao Yu

    2011-09-01

    Full Text Available Manila clam Ruditapes philippinarum is one of the most important economic species in shellfishery in China due to its wide geographic distribution and high tolerance to environmental changes (e.g., salinity, temperature. In addition, Manila clam is a good biomonitor/bioindicator in “Mussel Watch Programs” and marine environmental toxicology. However, there are several pedigrees of R. philippinarum distributed in the marine environment in China. No attention has been paid to the biological differences between various pedigrees of Manila clams, which may introduce undesirable biological variation in toxicology studies. In this study, we applied NMR-based metabolomics to detect the biological differences in two main pedigrees (White and Zebra of R. philippinarum and their differential responses to heavy metal exposures (Cadmium and Zinc using adductor muscle as a target tissue to define one sensitive pedigree of R. philippinarum as biomonitor for heavy metals. Our results indicated that there were significant metabolic differences in adductor muscle tissues between White and Zebra clams, including higher levels of alanine, glutamine, hypotaurine, phosphocholine and homarine in White clam muscles and higher levels of branched chain amino acids (valine, leucine and isoleucine, succinate and 4-aminobutyrate in Zebra clam muscles, respectively. Differential metabolic responses to heavy metals between White and Zebra clams were also found. Overall, we concluded that White pedigree of clam could be a preferable bioindicator/biomonitor in marine toxicology studies and for marine heavy metals based on the relatively high sensitivity to heavy metals.

  16. The influence of salinity on toxicological effects of arsenic in digestive gland of clam Ruditapes philippinarum using metabolomics

    Institute of Scientific and Technical Information of China (English)

    JI Chenglong; WU Huifeng; LIU Xiaoli; ZHAO Jianmin; YU Junbao; YIN Xiuli

    2013-01-01

    Ruditapes philippinarum,a clam that thrives in intertidal zones of various salinities,is a useful biomonitor to marine contaminants.We investigated the influence of dilution to 75% and 50% of normal seawater salinity (31.1) on the responses of the digestive gland of R.philippinarum to arsenic exposure (20 μg/L),using nuclear magnetic resonance (NMR)-based metabolomics.After acute arsenic exposure for 48 h,salinity-dependent differential metabolic responses were detected.In normal seawater,arsenic exposure increased the concentrations of branched-chain amino acids,and of threonine,proline,phosphocholine and adenosine,and it decreased the levels of alanine,hypotaurine,glucose,glycogen and ATP in the digestive glands.Differential changes in metabolic biomarkers observed at lower salinity (~23.3)included elevation of succinate,taurine and ATP,and depletion of branched-chain amino acids,threonine and glutamine.Unique effects of arsenic at the lowest salinity (~15.6) included down-regulation of glutamate,succinate and ADP,and up-regulation of phosphocholine.We conclude that salinity influences the metabolic responses of this clam to arsenic.

  17. Growth Performance of Larval and Juvenile Manila Clam (Ruditapes philippinarum) from Divergently Selected Individuals of a Full-Sib Family

    Institute of Scientific and Technical Information of China (English)

    HUO Zhongming; LI Xiaotong; SUN Qian; LI Yongren; ZHANG Xuekai; YAN Xiwu; YANG Feng

    2016-01-01

    In this study, the method of divergent selection was employed to test the larval and juvenile growth performance within a full-sib family of Manila clamRuditapes philippinarum. The 10% largest and 10% smallest clam individuals (on the basis of shell length) of a full-sib family were selected as parents for the fast and slow growing lines, respectively. The difference in shell length was significant among the three lines (fast, control, and slow) tested. The sequence of shell length were fast line>control line>slow line. The responses to selection, realized heritability, and genetic gain were 0.06%–0.81%, 0.04%–0.47% and 0.58%–18.89% in the fast direction, respectively; and were 0.14%–1.27%, 0.08%–0.73%, and 0.31%–49.03% in the slow direction, respectively. The re-sults suggested that there was a large portion of additive genetic variance affecting the growth in the full-sib family. Selection in the fast direction within the full-sib family would greatly improve the growth ofR. philippinarum.

  18. Caffeine impacts in the clam Ruditapes philippinarum: Alterations on energy reserves, metabolic activity and oxidative stress biomarkers.

    Science.gov (United States)

    Cruz, Diogo; Almeida, Ângela; Calisto, Vânia; Esteves, Valdemar I; Schneider, Rudolf J; Wrona, Frederick J; Soares, Amadeu M V M; Figueira, Etelvina; Freitas, Rosa

    2016-10-01

    Caffeine is known to be one of the most consumed psychoactive drugs. For this reason, caffeine is continuously released into the environment with potential impacts on inhabiting organisms. The current study evaluated the biochemical alterations induced in the clam species Ruditapes philippinarum after exposure for 28 days to caffeine (0.5, 3.0 and 18.0 μg/L). The results obtained showed that, with the increasing caffeine concentrations, an increase in clams defense mechanisms (such as antioxidant and biotransformation enzymes activity) was induced which was accompanied by an increase in protein content. Nevertheless, although an increase on defense mechanisms was observed, clams were not able to prevent cells from lipid peroxidation that increased with the increase of caffeine concentration. Furthermore, with the increase of exposure concentrations, clams increased their metabolic activity (measured by electron transport activity), reducing their energy reserves (glycogen content), to fight against oxidative stress. Overall, the present study demonstrated that caffeine may impact bivalves, even at environmentally relevant concentrations, inducing oxidative stress in organisms. The present study is an important contribution to address knowledge gaps regarding the impacts of long-term exposures to pharmaceuticals since most of the studies assessed the effects after acute exposures, most of them up to 96 h.

  19. Combined Effects of Temperature and Seston Concentration on the Physiological Energetics of the Manila Clam Ruditapes philippinarum.

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    Hee Yoon Kang

    Full Text Available The suspension-feeding Manila clam Ruditapes philippinarum is a native species of the western Pacific that is now widely distributed around the globe because of its commercial importance. To determine the adaptive physiological responses to changing thermal and nutritional conditions, clearance, filtration, feces production, ammonium excretion, respiration rates, and scope for growth (SFG were measured in adult clams. The clams were exposed to 24 treatments involving the combination of four water temperatures (8, 13, 18, and 23°C and six concentrations of suspended particulate matter (SPM: 9.5 to 350.5 mg L(-1. Physiological rates were standardized by using the mean (480 mg of tissue dry weights of experimental clams using allometric equations between physiological variables and tissue dry weight. Higher clearance rates were recorded at higher temperatures and lower SPM concentrations, and these rates decreased with increasing SPM concentration at individual temperatures. Consumed energy increased with increasing temperature and SPM concentration, peaking at around 100-200 mg L(-1 at 18-23°C. Whereas fecal energy was largely determined by SPM concentration, ammonia excretion was mainly governed by temperature. Respiration rate studies revealed a predominant quadratic effect of temperature on the metabolism, indicating a lack of acclimatory adjustment of metabolic rate to rising temperature. SFG values were positive under almost all the treatment conditions and were much higher at higher SPM concentrations (> 45 mg L(-1, with the highest level being recorded at 18°C and 100-200 mg L(-1 SPM. Increased filtration rate offset the increased metabolic cost at warm temperatures. Our holistic findings suggest that a high degree of physiological plasticity allows R. philippinarum to tolerate the wide range of temperatures and SPM concentrations that are found in tidal flats, accounting in part for the successful distribution of this species over a

  20. Combined Effects of Temperature and Seston Concentration on the Physiological Energetics of the Manila Clam Ruditapes philippinarum.

    Science.gov (United States)

    Kang, Hee Yoon; Lee, Young-Jae; Choi, Kwang-Sik; Park, Hyun Je; Yun, Sung-Gyu; Kang, Chang-Keun

    2016-01-01

    The suspension-feeding Manila clam Ruditapes philippinarum is a native species of the western Pacific that is now widely distributed around the globe because of its commercial importance. To determine the adaptive physiological responses to changing thermal and nutritional conditions, clearance, filtration, feces production, ammonium excretion, respiration rates, and scope for growth (SFG) were measured in adult clams. The clams were exposed to 24 treatments involving the combination of four water temperatures (8, 13, 18, and 23°C) and six concentrations of suspended particulate matter (SPM: 9.5 to 350.5 mg L(-1)). Physiological rates were standardized by using the mean (480 mg) of tissue dry weights of experimental clams using allometric equations between physiological variables and tissue dry weight. Higher clearance rates were recorded at higher temperatures and lower SPM concentrations, and these rates decreased with increasing SPM concentration at individual temperatures. Consumed energy increased with increasing temperature and SPM concentration, peaking at around 100-200 mg L(-1) at 18-23°C. Whereas fecal energy was largely determined by SPM concentration, ammonia excretion was mainly governed by temperature. Respiration rate studies revealed a predominant quadratic effect of temperature on the metabolism, indicating a lack of acclimatory adjustment of metabolic rate to rising temperature. SFG values were positive under almost all the treatment conditions and were much higher at higher SPM concentrations (> 45 mg L(-1)), with the highest level being recorded at 18°C and 100-200 mg L(-1) SPM. Increased filtration rate offset the increased metabolic cost at warm temperatures. Our holistic findings suggest that a high degree of physiological plasticity allows R. philippinarum to tolerate the wide range of temperatures and SPM concentrations that are found in tidal flats, accounting in part for the successful distribution of this species over a wide variety

  1. Food sources of the Manila clam Ruditapes philippinarum in intertidal areas: evidence from stable isotope analysis

    Institute of Scientific and Technical Information of China (English)

    ZHAO Liqiang; YAN Xiwu; YANG Feng

    2013-01-01

    Based on stable isotope analysis,we characterized the dietary regime of the Manila clam Ruditapesphilippinarum inhabiting intertidal areas along the Liaodong Peninsula,Northern China.Samples,including particulate organic matter (POM; n=30),benthic microalgae (BMI; n=30) and R.philippinarum (n=60),were collected from six sampling sites displaying the same ecological conditions.Of the two primary food sources,POM was more depleted in δ13C (-20.61‰ to-22.89‰) than BMI was (-13.90‰ to-16.66‰).With respect to 15N,BMI was more enriched (2.90‰ to 4.07‰) than POM was (4.13‰ to 5.12‰).The δ13C values of R.philippinarum ranged from-18.78‰ to-19.35‰ and the δ15N values from 7.96‰ to 8.63‰,which were intermediate between the POM and BMI values.In a two-source isotope mixing model,we estimated the relative contributions of POM and BMI to the diet of R.philippinarum to be 74.2% and 25.8%,respectively.We conclude that R.philippinarum feeds mainly on POM,and BMI is also an important supplemental food source in intertidal areas.

  2. Toxicological effects induced by cadmium in gills of Manila clam ruditapes philippinarum using NMR-based metabolomics

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Linbao; Liu, Xiaoli; You, Liping; Zhou, Di [Key Laboratory of Coastal Zone Environment Processes, CAS, Shandong Provincial Key Laboratory of Coastal Zone Environment Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai (China); The Graduate School of Chinese Academy of Sciences, Beijing (China); Yu, Junbao; Zhao, Jianmin; Wu, Huifeng [Key Laboratory of Coastal Zone Environment Processes, CAS, Shandong Provincial Key Laboratory of Coastal Zone Environment Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai (China); Feng, Jianghua [Department of Electronic Science, Fujian Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen (China)

    2011-11-15

    Cadmium (Cd) has become an important heavy metal contaminant in the sediment and seawater along the Bohai Sea and been of great ecological risk due to its toxic effects to marine organisms. In this work, the toxicological effects caused by environmentally relevant concentrations (10 and 40 {mu}g L{sup -1}) of Cd were studied in the gill tissues of Manila clam Ruditapes philippinarum after exposure for 24, 48, and 96 h. Both low (10 {mu}g L{sup -1}) and high (40 {mu}g L{sup -1}) doses of Cd caused the disturbances in energy metabolism and osmotic regulation and neurotoxicity based on the metabolic biomarkers such as succinate, alanine, branched chain amino acids, betaine, hypotaurine, and glutamate in clam gills after 24 h of exposure. However, the recovery of toxicological effects of Cd after exposure for 96 h was obviously observed in clam to Cd exposures. Overall, these results indicated that NMR-based metabolomics was applicable to elucidate the toxicological effects of heavy metal contaminants in the marine bioindicator. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Following the infection process of vibriosis in Manila clam (Ruditapes philippinarum) larvae through GFP-tagged pathogenic Vibrio species.

    Science.gov (United States)

    Dubert, Javier; Nelson, David R; Spinard, Edward J; Kessner, Linda; Gomez-Chiarri, Marta; da Costa, Fiz; Prado, Susana; Barja, Juan L

    2016-01-01

    Vibriosis represents the main bottleneck for the larval production process in shellfish aquaculture. While the signs of this disease in bivalve larvae are well known, the infection process by pathogenic Vibrio spp. during episodes of vibriosis has not been elucidated. To investigate the infection process in bivalves, the pathogens of larvae as V. tubiashii subsp. europaensis, V. neptunius and V. bivalvicida were tagged with green fluorescent protein (GFP). Larvae of Manila clam (Ruditapes philippinarum) were inoculated with the GFP-labeled pathogens in different infection assays and monitored by microscopy. Manila clam larvae infected by distinct GFP-tagged Vibrio spp. in different challenges showed the same progression in the infection process, defining three infection stages. GFP-tagged Vibrio spp. were filtered by the larvae through the vellum and entered in the digestive system through the esophagus and stomach and colonized the digestive gland and particularly the intestine, where they proliferated during the first 2h of contact (Stage I), suggesting a chemotactic response. Then, GFP-tagged Vibrio spp. expanded rapidly to the surrounding organs in the body cavity from the dorsal to ventral region (Stage II; 6-8h), colonizing the larvae completely at the peak of infection (Stage III) (14-24h). Results demonstrated for the first time that the vibriosis is asymptomatic in Manila clam larvae during the early infection stages. Thus, the early colonization and the rapid proliferation of Vibrio pathogens within the body cavity supported the sudden and fatal effect of the vibriosis, since the larvae exhibited the first signs of disease when the infection process is advanced. As a first step in the elucidation of the potential mechanisms of bacterial pathogenesis in bivalve larvae the enzymatic activities of the extracellular products released from the wild type V. neptunius, V. tubiashii subsp. europaensis and V. bivalvicida were determined and their cytotoxicity was

  4. Thermal dependence of clearance and metabolic rates in slow- and fast-growing spats of manila clam Ruditapes philippinarum.

    Science.gov (United States)

    Tamayo, David; Ibarrola, Irrintzi; Navarro, Enrique

    2013-10-01

    Thermal dependence of clearance rate (CR: l h(-1)), standard (SMR: J h(-1)) and routine metabolic rates (RMR: J h(-1)), were analyzed in fast (F)- and slow (S)-growing juveniles of the clam Ruditapes philippinarum. Physiological rates were measured at the maintenance temperature (17 °C), and compared with measurements performed at 10 and 24 °C after 16 h and 14 days to analyze acute and acclimated responses, respectively. Metabolic rates (both RMR and SMR) differed significantly between F and S seeds, irrespective of temperature. Mass-specific CRs were not different for F and S seeds but were significantly higher in F clams for rates standardized according to allometric size-scaling rules. Acute thermal dependency of CR was equal for F and S clams: mean Q 10 were ≈3 and 2 in temperature ranges of 10-17 and 17-24 °C, respectively. CR did not change after 2 weeks of acclimation to temperatures. Acute thermal effects on SMR were similar in both groups (Q 10 ≈ 1 and 1.6 in temperature ranges of 10-17 and 17-24 °C, respectively). Large differences between groups were found in the acute thermal dependence of RMR: Q 10 in F clams (≈1.2 and 1.9 at temperature ranges of 10-17 and 17-24 °C, respectively) were similar to those found for SMR (Q 10 = 1.0 and 1.7). In contrast, RMR of S clams exhibited maximum thermal dependence (Q 10 = 3.1) at 10-17 °C and become depressed at higher temperatures (Q 10 = 0.9 at 17-24 °C). A recovery of RMR in S clams was recorded upon acclimation to 24 °C. Contrasting metabolic patterns between fast and slow growers are interpreted as a consequence of differential thermal sensitivity of the fraction of metabolism associated to food processing and assimilation.

  5. New polymorphic microsatellite markers derived from hemocyte cDNA library of Manila clam Ruditapes philippinarum challenged by the protozoan parasite Perkinsus olseni

    Science.gov (United States)

    Kang, Hyun-Sil; Hong, Hyun-Ki; Park, Kyung-Il; Cho, Moonjae; Youn, Seok-Hyun; Choi, Kwang-Sik

    2017-02-01

    Manila clam Ruditapes philippinarum is one of the most important benthic animals in the coastal north Pacific region, where clam populations have been mixed genetically through trade and aquaculture activities. Accordingly, identification of the genetically different clam populations has become one of the most important issues to manage interbreeding of the local and introduced clam populations. To identify genetically different populations of clam populations, we developed 11 expressed sequence tag (EST)-microsatellite loci (i.e., simple sequence repeat, SSR) from 1,128 clam hemocyte cDNA clones challenged by the protozoan parasite Perkinsus olseni. Genotype analysis using the markers developed in this study demonstrated that clams from a tidal flat on the west coast contained 6 to 19 alleles per locus, and a population from Jeju Island had 4 to 20 alleles per locus. The expected heterozygosity of the 2 clam populations ranged from 0.472 to 0.919 for clams from the west coast, and 0.494 to 0.919 for clams from Jeju Island, respectively. Among the 11 loci discovered in this study, 7 loci significantly deviated from the Hardy-Weinberg equilibrium after Bonferroni correction. The 5 loci developed in this study also successfully amplified the SSRs of R. variegatus, a clam species taxonomically very close to R. philippinarum, from Hong Kong and Jeju Island. We believe that the 11 novel polymorphic SSR developed in this study can be utilized successfully in Manila clam genetic diversity analysis, as well as in genetic discrimination of different clam populations.

  6. New polymorphic microsatellite markers derived from hemocyte cDNA library of Manila clam Ruditapes philippinarum challenged by the protozoan parasite Perkinsus olseni

    Science.gov (United States)

    Kang, Hyun-Sil; Hong, Hyun-Ki; Park, Kyung-Il; Cho, Moonjae; Youn, Seok-Hyun; Choi, Kwang-Sik

    2017-03-01

    Manila clam Ruditapes philippinarum is one of the most important benthic animals in the coastal north Pacific region, where clam populations have been mixed genetically through trade and aquaculture activities. Accordingly, identification of the genetically different clam populations has become one of the most important issues to manage interbreeding of the local and introduced clam populations. To identify genetically different populations of clam populations, we developed 11 expressed sequence tag (EST)-microsatellite loci (i.e., simple sequence repeat, SSR) from 1,128 clam hemocyte cDNA clones challenged by the protozoan parasite Perkinsus olseni. Genotype analysis using the markers developed in this study demonstrated that clams from a tidal flat on the west coast contained 6 to 19 alleles per locus, and a population from Jeju Island had 4 to 20 alleles per locus. The expected heterozygosity of the 2 clam populations ranged from 0.472 to 0.919 for clams from the west coast, and 0.494 to 0.919 for clams from Jeju Island, respectively. Among the 11 loci discovered in this study, 7 loci significantly deviated from the Hardy-Weinberg equilibrium after Bonferroni correction. The 5 loci developed in this study also successfully amplified the SSRs of R. variegatus, a clam species taxonomically very close to R. philippinarum, from Hong Kong and Jeju Island. We believe that the 11 novel polymorphic SSR developed in this study can be utilized successfully in Manila clam genetic diversity analysis, as well as in genetic discrimination of different clam populations.

  7. Substantial changes in hemocyte parameters of Manila clam Ruditapes philippinarum two years after the Hebei Spirit oil spill off the west coast of Korea.

    Science.gov (United States)

    Hong, Hyun-Ki; Donaghy, Ludovic; Kang, Chang-Keun; Kang, Hyun-Sil; Lee, Hee-Jung; Park, Heung-Sik; Choi, Kwang-Sik

    2016-07-15

    Two years after the Hebei Spirit oil spill occurred off the west coast of Korea, we determined sub-lethal effects of the spilled oil on hemocyte parameters of Ruditapes philippinarum in the damaged areas. Clams in the spilled sites displayed unusually high proportion of granulocytes, which may result in higher phagocytosis capacity and reactive oxygen species production. Hemocytes in clams from the polluted sites also displayed less DNA damage and mortality than in the control site, possibly due to a faster phagocytosis of the impaired cells. Glycogen, the major energetic reserve, was depleted in clams from the spilled sites, potentially due to energetic consumption for maintenance of a large pool of granulocytes, detoxification processes and oxidative stress. Modified hemocyte parameters in clams in the spilled area, may reflect sub-lethal physiological stresses caused by the residual oils in the sediment, in conjunction with environmental modifications such as food availability and pathogens pattern.

  8. Seasonal Changes in Glycogen Contents in Various Tissues of the Edible Bivalves, Pen Shell Atrina lischkeana, Ark Shell Scapharca kagoshimensis, and Manila Clam Ruditapes philippinarum in West Japan

    Directory of Open Access Journals (Sweden)

    Tatsuya Yurimoto

    2015-01-01

    Full Text Available The types of tissues accumulating glycogen and seasonal changes in glycogen content were investigated in the following shell species: pen shell Atrina lischkeana, ark shell Scapharca kagoshimensis, and Manila clam Ruditapes philippinarum. Comparison of the results showed that the adductor muscle or foot was the main glycogen reservoir and the levels varied seasonally. The adductor muscle in the pen shell showed higher glycogen content during spring and lower content during autumn. The ark shell, on the other hand, showed higher content during winter and spring and lower content during summer and autumn, while the Manila clam showed higher glycogen content during spring and summer and lower content during autumn and winter. These results revealed that the adductor muscle in pen shells and the foot in ark shells and Manila clams act as the main storage tissues for glycogen in the three species studied and that these tissues are suitable to analyze glycogen prevalence to estimate individual physiological condition.

  9. Effects of environmental and biological conditions on the recruitment and growth of the Manila clam Ruditapes philippinarum on the west coast of Korea

    Science.gov (United States)

    Kim, Sang Lyeol; Kwon, Soon Hyun; Lee, Hyung-Gon; Yu, Ok Hwan

    2017-03-01

    The distribution of the Manila clam Ruditapes philippinarum, which is often dominant in intertidal zones, is influenced by both environmental and biological conditions. However, there have been few comprehensive studies on the interactive effects of these two groups of factors. The present study examined the environmental and biological parameters determining the population dynamics of the clams that is a dominant component of the intertidal communities of Euhangri and Padori on the west coast of Korean peninsula. We collected R. philippinarum and other members of the macrobenthos (> 1 mm long) monthly from 0.25 m2 quadrats deployed in the intertidal zones at Euhangri, Taean, and Padori during the period from August 2013 to January 2015. Physicochemical parameters of the water and sediment were measured at the same time. Water temperature and salinity is high and low in the summer to winter, respectively. While mean grain size of the sediment was higher at Euhangri than at Padori, total mean density of R. philippinarum was higher at Euhangri (325 ind./ 0.25 m2 at Padori vs. 194 ind./0.25 m2 at Euhangri). Settled spat (food supply, will optimize production of these commercial clams.

  10. Risk assessment of TBT in the Japanese short-neck clam ( Ruditapes philippinarum) of Tokyo Bay using a chemical fate model

    Science.gov (United States)

    Horiguchi, Fumio; Nakata, Kisaburo; Ito, Naganori; Okawa, Ken

    2006-12-01

    A risk assessment of Tributyltin (TBT) in Tokyo Bay was conducted using the Margin of Exposure (MOE) method at the species level using the Japanese short-neck clam, Ruditapes philippinarum. The assessment endpoint was defined to protect R. philippinarum in Tokyo Bay from TBT (growth effects). A No Observed Effect Concentration (NOEC) for this species with respect to growth reduction induced by TBT was estimated from experimental results published in the scientific literature. Sources of TBT in this study were assumed to be commercial vessels in harbors and navigation routes. Concentrations of TBT in Tokyo Bay were estimated using a three-dimensional hydrodynamic model, an ecosystem model and a chemical fate model. MOEs for this species were estimated for the years 1990, 2000, and 2007. Estimated MOEs for R. philippinarum for 1990, 2000, and 2007 were approximately 1-3, 10, and 100, respectively, indicating a declining temporal trend in the probability of adverse growth effects. A simplified software package called RAMTB was developed by incorporating the chemical fate model and the databases of seasonal flow fields and distributions of organic substances (phytoplankton and detritus) in Tokyo Bay, simulated by the hydrodynamic and ecological model, respectively.

  11. Target organs of the Manila clam Ruditapes philippinarum for studying metal accumulation and biomarkers in pollution monitoring: laboratory and in-situ transplantation experiments.

    Science.gov (United States)

    Won, Eun-Ji; Kim, Kyung-Tae; Choi, Jin-Young; Kim, Eun-Soo; Ra, Kongtae

    2016-08-01

    To characterize the target organs of the Manila clam Ruditapes philippinarum for use in environmental study, the accumulation of trace metals and three biomarkers was measured in different organs. Exposure with Cu and Pb carried out under laboratory conditions revealed a linear uptake of metals throughout the experimental period in each tissue. In particular, significant increase was observed in gills and mantle. The increase of intracellular reactive oxygen species showed the great potential of gills as a target tissue for both Cu and Pb exposure. The highest activity of glutathione S-transferase and their relative increase in activity were also observed in gills. Metallothionein-like protein levels, however, increased greatly in the digestive gland and mantle during Cu and Pb exposure, respectively, although all tissues, except the foot, showed significant changes after 24 h of metal exposure. In the field study, the highest concentration of metals was recorded in the gills and mantle, accounting for over 50 % of the total accumulated metal in all sites. Additionally, Cu and Pb increased significantly in these two organs, respectively. However, the order of accumulation rate in laboratory exposure was not concomitant with those of the lab-based study, suggesting that different routes of metal uptake and exposure duration induce distinct partitioning of metals and regulating system in R. philippinarum. These series of exposure studies demonstrated that gills, mantle, and digestive gland in R. philippinarum are potential target tissues in environmental monitoring study using metal concentrations and biomarkers.

  12. Distribution of butyltins (TBT, DBT, MBT) in sediments of Gulf of Cádiz (Spain) and its bioaccumulation in the clam Ruditapes philippinarum.

    Science.gov (United States)

    Garg, A; Antón-Martín, R; García-Luque, E; Riba, I; DelValls, T A

    2009-11-01

    Surface sediment samples were analyzed for organotins namely tributyltin (TBT), dibutyltin and monobutyltin from six areas located in the Gulf of Cádiz (14 stations), Spain. The total butyltin ranged between undetected and 1,580 ng Sn g(-1). TBT generally prevailed in most of the samples, suggesting fresh inputs of butyltin compounds and/or less degradation of TBT. The observed levels of butyltins at several sites are much higher than that required to induce toxic effect on marine organisms, suggesting that these sediments are polluted with butyltin compounds. The clam Ruditapes philippinarum was used for studying bioaccumulation of butyltins by exposing them to contaminated sediments from the Gulf of Cádiz over a period of 28 days under laboratory conditions. Biota-sediment accumulation factor (BSAF) ranged from 0.44 to 3.99.

  13. Molecular cloning, characterization, and expression analysis of a gonadotropin-releasing hormone-like cDNA in the clam, Ruditapes philippinarum.

    Science.gov (United States)

    Song, Ying; Miao, Jingjing; Cai, Yuefeng; Pan, Luqing

    2015-11-01

    Gonadotropin-releasing hormone (GnRH) is a key neuropeptide regulating reproduction in vertebrates. In the present study, we have cloned and identified the cDNA sequence of the prepro-GnRH (rp-GnRH) in the Manila clam Ruditapes philippinarum. The open reading frame encodes a protein of 94 amino acids, which consists of a signal peptide, a GnRH dodecapeptide, a cleavage site, and a GnRH-associated peptide. These deduced peptides were highly homologous to that reported for other molluscs. We used temperature control to promote gonadal development of the clams. The mRNA expression of rp-GnRH in the visceral ganglia from clams at different reproductive stages was determined by quantitative RT-PCR. The levels of steroids progesterone (P), testosterone (T), and estradiol-17β (E2) in the hemolymph of the corresponding clam were measured by ELISA. The rp-GnRH mRNA was highly expressed at the gonadal early development stage. Concentrations of P, T, and E2 also increased at the early development stage in both sexes. Positive significant correlations between rp-GnRH expression and P content as well as between rp-GnRH expression and T content were observed throughout the gonadal maturation. The results from this study may help to better understand the physiological functions of the native forms of GnRH-like peptides and the actions of GnRH on sex steroids release in bivalve molluscs.

  14. Molecular and histological identification of Marteilioides infection in Suminoe Oyster Crassostrea ariakensis, Manila Clam Ruditapes philippinarum and Pacific Oyster Crassostrea gigas on the south coast of Korea.

    Science.gov (United States)

    Limpanont, Yanin; Yanin, Limpanont; Kang, Hyun-Sil; Hong, Hyun-Ki; Jeung, Hee-Do; Kim, Bong-Kyu; Le, Thanh Cuong; Kim, Young-Ok; Choi, Kwang-Sik

    2013-11-01

    The oyster ovarian parasite Marteilioides chungmuensis has been reported from Korea and Japan, damaging the oyster industries. Recently, Marteilioides-like organisms have been identified in other commercially important marine bivalves. In this study, we surveyed Marteilioides infection in the Manila clam Ruditapes philippinarum, Suminoe oyster Crassostrea ariakensis, and Pacific oyster Crassostrea gigas, using histology and Marteilioides-specific small subunit (SSU) rDNA PCR. The SSU rDNA sequence of M. chungmuensis (1716 bp) isolated from C. gigas in Tongyoung bay was 99.9% similar to that of M. chungmuensis reported in Japan. Inclusions of multi-nucleated bodies in the oocytes, typical of Marteilioides infection, were identified for the first time in Suminoe oysters. The SSU rDNA sequence of a Marteilioides-like organism isolated from Suminoe oysters was 99.9% similar to that of M. chungmuensis. Marteilioides sp. was also observed from 7 Manila clams of 1840 individuals examined, and the DNA sequences of which were 98.2% similar to the known sequence of M. chungmuensis. Unlike Marteilioides infection of Pacific oysters, no remarkable pathological symptoms, such as large multiple lumps on the mantle, were observed in infected Suminoe oysters or Manila clams. Distribution of the infected Manila clams, Suminoe oysters and Pacific oysters was limited to small bays on the south coast, suggesting that the southern coast is the enzootic area of Marteilioides infection.

  15. De Novo assembly of the Manila clam Ruditapes philippinarum transcriptome provides new insights into expression bias, mitochondrial doubly uniparental inheritance and sex determination.

    Science.gov (United States)

    Ghiselli, Fabrizio; Milani, Liliana; Chang, Peter L; Hedgecock, Dennis; Davis, Jonathan P; Nuzhdin, Sergey V; Passamonti, Marco

    2012-02-01

    Males and females share the same genome, thus, phenotypic divergence requires differential gene expression and sex-specific regulation. Accordingly, the analysis of expression patterns is pivotal to the understanding of sex determination mechanisms. Many bivalves are stable gonochoric species, but the mechanism of gonad sexualization and the genes involved are still unknown. Moreover, during the period of sexual rest, a gonad is not present and sex cannot be determined. A mechanism associated with germ line differentiation in some bivalves, including the Manila clam Ruditapes philippinarum, is the doubly uniparental inheritance (DUI) of mitochondria, a variation of strict maternal inheritance. Two mitochondrial lineages are present, one transmitted through eggs and the other through sperm, as well as a mother-dependent sex bias of the progeny. We produced a de novo annotation of 17,186 transcripts from R. philippinarum and compared the transcriptomes of males and females and identified 1,575 genes with strong sex-specific expression and 166 sex-specific single nucleotide polymorphisms, obtaining preliminary information about genes that could be involved in sex determination. Then we compared the transcriptomes between a family producing predominantly females and a family producing predominantly males to identify candidate genes involved in regulation of sex-specific aspects of DUI system, finding a relationship between sex bias and differential expression of several ubiquitination genes. In mammalian embryos, sperm mitochondria are degraded by ubiquitination. A modification of this mechanism is hypothesized to be responsible for the retention of sperm mitochondria in male embryos of DUI species. Ubiquitination can additionally regulate gene expression, playing a role in sex determination of several animals. These data enable us to develop a model that incorporates both the DUI literature and our new findings.

  16. Does the antibiotic amoxicillin affect haemocyte parameters in non-target aquatic invertebrates? The clam Ruditapes philippinarum and the mussel Mytilus galloprovincialis as model organisms.

    Science.gov (United States)

    Matozzo, Valerio; Bertin, Valeria; Battistara, Margherita; Guidolin, Angelica; Masiero, Luciano; Marisa, Ilaria; Orsetti, Alessandro

    2016-08-01

    Amoxicillin (AMX) is one of the most widely used antibiotics worldwide, and its levels in aquatic ecosystems are expected to be detectable. At present, information concerning the toxic effects of AMX on non-target aquatic organisms, such as bivalves, is scarce. Consequently, in this study, we investigated for the first time the effects of AMX on the haemocyte parameters of two bivalve species, the clam Ruditapes philippinarum and the mussel Mytilus galloprovincialis, which share the same habitat in the Lagoon of Venice, in order to compare the relative sensitivity of the two species. The bivalves were exposed to 100, 200 and 400 μg AMX/L for 1, 3 and 7 days, and the effects on the total haemocyte count (THC), the diameter and volume of the haemocytes, haemocyte proliferation, lactate dehydrogenase (LDH) activity in cell-free haemolymph, the haemolymph pH, and the formation of micronuclei were evaluated. The actual concentrations of AMX in the seawater samples from the experimental tanks were also measured. Overall, the obtained results demonstrated that AMX affected slightly the haemocyte parameters of bivalves. In addition, no clear differences in terms of sensitivity to AMX exposure were recorded between the two bivalve species.

  17. In vitro exposure of haemocytes of the clam Ruditapes philippinarum to titanium dioxide (TiO2) nanoparticles: nanoparticle characterisation, effects on phagocytic activity and internalisation of nanoparticles into haemocytes.

    Science.gov (United States)

    Marisa, Ilaria; Marin, Maria Gabriella; Caicci, Federico; Franceschinis, Erica; Martucci, Alessandro; Matozzo, Valerio

    2015-02-01

    The continuous growth of nanotechnology and nano-industries, the considerable increase of products containing nanoparticles (NPs) and the potential release of NPs in aquatic environments suggest a need to study NP effects on aquatic organisms. In this context, in vitro assays are commonly used for evaluating or predicting the negative effects of chemicals and for understanding their mechanisms of action. In this study, a physico-chemical characterisation of titanium dioxide NPs (n-TiO2) was performed, and an in vitro approach was used to investigate the effects of n-TiO2 on haemocytes of the clam Ruditapes philippinarum. In particular, the effects on haemocyte phagocytic activity were evaluated in two different experiments (with and without pre-treatment of haemocytes) by exposing cells to P25 n-TiO2 (0, 1 and 10 μg/mL). In addition, the capability of n-TiO2 to interact with clam haemocytes was evaluated with a transmission electron microscope (TEM). In this study, n-TiO2 particles showed a mean diameter of approximately 21 nm, and both anatase (70%) and rutile (30%) phases were revealed. In both experiments, n-TiO2 significantly decreased the phagocytic index compared with the control, suggesting that NPs are able to interfere with cell functions. The results of the TEM analysis support this hypothesis. Indeed, we observed that TiO2 NPs interact with cell membranes and enter haemocyte cytoplasm and vacuoles after 60 min of exposure. To the best of our knowledge, this is the first study demonstrating the internalisation of TiO2 NPs into R. philippinarum haemocytes. The present study can contribute to the understanding of the mechanisms of action of TiO2 NPs in bivalve molluscs, at least at the haemocyte level.

  18. A metabolic profile in Ruditapes philippinarum associated with growth-promoting effects of alginate hydrolysates

    Science.gov (United States)

    Yamasaki, Yasuhiro; Taga, Shigeru; Kishioka, Masanobu; Kawano, Shuichi

    2016-07-01

    The aim of this study is to demonstrate the growth-promoting effect of alginate hydrolysates (AHs) on the Manila clam Ruditapes philippinarum, and to verify the physiological change occurring within a living R. philippinarum stimulated by AHs. We show that growth of clams was dramatically promoted by supplementing a diet of the diatom Chaetoceros neogracile with AHs at 4 mg/mL. Furthermore, metabolomics indicates that each state of starvation, food satiation, and sexual maturation have a characteristic pattern. In the groups given AHs in addition to C. neogracile in particular, excess carbohydrate was actively utilized for the development of reproductive tissue. In contrast, it appeared that clams in the groups given C. neogracile only were actively growing, utilizing their adequate carbohydrate resources. Meanwhile, the unfed groups have slowed growth because of the lack of an energy source. Hence, supplementation of AHs in addition to the algal diet may be an inexpensive way to shorten the rearing period of R. philippinarum. Moreover, metabolomics can evaluate the growth condition of R. philippinarum in a comprehensive way, and this approach is crucially important for not only the development of a mass culture method but also for the conservation of the clam resource in the field.

  19. Occurrence of Vibrio parahaemolyticus, Vibrio cholerae and Vibrio vulnificus in the clam Ruditapes philippinarum (Adams & Reeve, 1850 from Emilia Romagna and Sardinia, Italy

    Directory of Open Access Journals (Sweden)

    Pier Luca Passalacqua

    2016-04-01

    Full Text Available Marine vibrios, Vibrio parahaemolyticus, V. vulnificus and V. cholerae are responsible of the majority of food-borne human infections by consumption of bivalve shellfish. The aim of the present study was to ascertain the occurrence of these bacteria, and their potential pathogenicity, in the Manila clam R. philippinarum from Emilia Romagna (ER and Sardinia (SR regions, Italy. Isolation was performed on CHROMagarTM vibrio with subculture on (thiosulfate-citrate-bile salts-sucrose Agar and m-modified-cellobiose-polymyxin bcolistin (-CPC Agar. Suspected strains were purified, biochemically characterized and genotyped by simplex polymerase chain reaction (PCR for the specie-specific and pathogenic gene markers: V. parahaemolyticus (toxRP, tdh and trh; V. vulnificus (vvhA, hsp, vcgC, vcgE, CPS operon allele 1, CPS operon allele 2, 16s-rRNA operon allele A, 16s-rRNA operon allele B; V. cholerae (toxRC, hlya, tcpI, tcpA, ctxA, ctxB, stn/sto. Moreover a multiplex PCR was applied to the SR bivalve shellfish, for the simultaneous detection of the three targets directly on homogenate samples, targeting the species-specific gene for V. cholerae (toxRC, V. parahaemolyticus (toxRP and V. vulnificus (vvhA. As a result of phenotyping and genotyping of isolates, bivalve shellfish from ER resulted positive for V. parahaemolyticus (27.8% and V. vulnificus (10.1%, but negative for V. cholerae. Shellfish from SR resulted positive for V. parahaemolyticus (30.3%, V. vulnificus (6.1% and V. cholerae (3%. No significant differences emerged between the two areas (P>0.05.

  20. Occurrence of Vibrio Parahaemolyticus, Vibrio Cholerae and Vibrio Vulnificus in the Clam Ruditapes Philippinarum (Adams & Reeve, 1850) from Emilia Romagna and Sardinia, Italy.

    Science.gov (United States)

    Passalacqua, Pier Luca; Zavatta, Emanuele; Bignami, Giorgia; Serraino, Andrea; Serratore, Patrizia

    2016-01-18

    Marine vibrios, Vibrio parahaemolyticus, V. vulnificus and V. cholerae are responsible of the majority of food-borne human infections by consumption of bivalve shellfish. The aim of the present study was to ascertain the occurrence of these bacteria, and their potential pathogenicity, in the Manila clam R. philippinarum from Emilia Romagna (ER) and Sardinia (SR) regions, Italy. Isolation was performed on CHROMagar(TM) vibrio with subculture on (thiosulfate-citrate-bile salts-sucrose) Agar and m-modified-cellobiose-polymyxin b-colistin (-CPC) Agar. Suspected strains were purified, biochemically characterized and genotyped by simplex polymerase chain reaction (PCR) for the specie-specific and pathogenic gene markers: V. parahaemolyticus (toxRP, tdh and trh); V. vulnificus (vvhA, hsp, vcgC, vcgE, CPS operon allele 1, CPS operon allele 2, 16s-rRNA operon allele A, 16s-rRNA operon allele B; V. cholerae (toxRC, hlya, tcpI, tcpA, ctxA, ctxB, stn/sto). Moreover a multiplex PCR was applied to the SR bivalve shellfish, for the simultaneous detection of the three targets directly on homogenate samples, targeting the species-specific gene for V. cholerae (toxRC), V. parahaemolyticus (toxRP) and V. vulnificus (vvhA). As a result of phenotyping and genotyping of isolates, bivalve shellfish from ER resulted positive for V. parahaemolyticus (27.8%) and V. vulnificus (10.1%), but negative for V. cholerae. Shellfish from SR resulted positive for V. parahaemolyticus (30.3%), V. vulnificus (6.1%) and V. cholerae (3%). No significant differences emerged between the two areas (P>0.05).

  1. Occurrence of Vibrio Parahaemolyticus, Vibrio Cholerae and Vibrio Vulnificus in the Clam Ruditapes Philippinarum (Adams & Reeve, 1850) from Emilia Romagna and Sardinia, Italy

    Science.gov (United States)

    Passalacqua, Pier Luca; Zavatta, Emanuele; Bignami, Giorgia; Serraino, Andrea

    2016-01-01

    Marine vibrios, Vibrio parahaemolyticus, V. vulnificus and V. cholerae are responsible of the majority of food-borne human infections by consumption of bivalve shellfish. The aim of the present study was to ascertain the occurrence of these bacteria, and their potential pathogenicity, in the Manila clam R. philippinarum from Emilia Romagna (ER) and Sardinia (SR) regions, Italy. Isolation was performed on CHROMagarTM vibrio with subculture on (thiosulfate-citrate-bile salts-sucrose) Agar and m-modified-cellobiose-polymyxin b-colistin (-CPC) Agar. Suspected strains were purified, biochemically characterized and genotyped by simplex polymerase chain reaction (PCR) for the specie-specific and pathogenic gene markers: V. parahaemolyticus (toxRP, tdh and trh); V. vulnificus (vvhA, hsp, vcgC, vcgE, CPS operon allele 1, CPS operon allele 2, 16s-rRNA operon allele A, 16s-rRNA operon allele B; V. cholerae (toxRC, hlya, tcpI, tcpA, ctxA, ctxB, stn/sto). Moreover a multiplex PCR was applied to the SR bivalve shellfish, for the simultaneous detection of the three targets directly on homogenate samples, targeting the species-specific gene for V. cholerae (toxRC), V. parahaemolyticus (toxRP) and V. vulnificus (vvhA). As a result of phenotyping and genotyping of isolates, bivalve shellfish from ER resulted positive for V. parahaemolyticus (27.8%) and V. vulnificus (10.1%), but negative for V. cholerae. Shellfish from SR resulted positive for V. parahaemolyticus (30.3%), V. vulnificus (6.1%) and V. cholerae (3%). No significant differences emerged between the two areas (P>0.05). PMID:27800436

  2. Intra-specific diet shift in manila clams (Ruditapes philippinarum) as revealed by carbon and nitrogen stable isotopes and fatty acid biomarker

    Science.gov (United States)

    Suh, Y.; Shin, K.

    2011-12-01

    Manila clams sampled in Seonjae Island, Korea with shell lengths (SL) below 19.76 mm in average showed a significantly depleted carbon and nitrogen isotope values (Pnutrition from both P. tricornutum and aggregated organic matter that consists of dead or decomposed microalgae or other detritus. Bigger size groups (10.92±0.34 mm and 14.81±0.25 mm) obtained most of their energy from P.tricorutum and also from other phytoplankton unlike the biggest size group (21.15±1.02 mm) that feeds mainly on fresh microalgae of all diets fed. This variation in diet reveals that smaller clams mostly inhale dead or decomposed microalgae that sinks on the bottom while the bigger clams uptake more fresh ones that are still alive. This variation in feeding behavior could have been caused by morphological constraints such as limited siphon length. The results suggest that manila clams greater than and below 19.76 mm in average have different feeding behavior and P. tricornutum and I. galbana were the two most preferred diets for manila clams cultured in IFHRI. The result of fatty acid composition of manila clams in relation to size or growth rate suggests that fast growing clams would have rapid metabolism of fatty acids not required by the animals and an accumulation of the essential fatty acids (PUFA). In addition, their higher energy requirement and more active state of development would further diminish lipid reserve of the species.

  3. Isozyme analysis on the populations of Ruditapes philippinarum

    Science.gov (United States)

    Ren, Yiping; Gao, Tianxiang; Yang, Tianyan

    2006-01-01

    Horizontal starch gel electrophoresis was used to investigate the genetic structure of six populations of Ruditapes philippinarum in the coast of China. Seven enzymes revealed eleven putative loci, and seven of them were polymorphic, PGM *, MDH-1*, MDH-3 *, LAP-1 *, LAP-2 *, MPI-1 * and MPI-2 *. The proportions of polymorphic loci of R. philippinarum populations varied from 0.454 5 to 0.636 4. The values of observed and expected heterozygosities were from 0.039 4 to 0.154 5 and from 0.1111 to 0.2385, respectively. Nei's genetic distance varied from 0.003 3 to 0.025 3 with an average of 0.013 5. It is suggested that the genetic diversity of R. philippinarum was high.

  4. Isozyme Analysis on the Populations of Ruditapes philippinarum

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Horizontal starch gel electrophoresis was used to investigate the genetic structure of six populations of Ruditapes philippinarum in the coast of China. Seven enzymes revealed eleven putative loci, and seven of them were polymorphic, PGM* , MDH- 1* , MDH-3* , LAP- 1* , LAP- 2* , MPI- 1* and MPI- 2* . The proportions of polymorphic loci of R . philippinarum populations varied from 0 . 454 5 to 0 . 636 4. The values of observed and expected heterozygosities were from 0 . 039 4 to 0 . 154 5 and from 0 . 111 1 to 0 . 238 5, respectively. Nei's genetic distance varied from 0 . 003 3 to 0 . 025 3 with an average of 0 . 013 5. It is suggested that the genetic diversity of R . philippinarum was high.

  5. Correlation between perkinsosis and growth in clams Ruditapes spp.

    Science.gov (United States)

    Dang, Cécile; de Montaudouin, Xavier; Binias, Cindy; Salvo, Flora; Caill-Milly, Nathalie; Bald, Juan; Soudant, Philippe

    2013-11-06

    Perkinsosis is one of the most widespread diseases affecting commercially important species of molluscs globally. We examined the impact of Perkinsus spp. on shell growth at the individual scale in 2 clam species: Ruditapes decussatus from Mundaka Estuary (Spain) and R. philippinarum from Arcachon Bay (France). At Arcachon, 2 contrasting sites in terms of environment and Perkinsus olseni presence were chosen: Arguin (disease-free) and Ile aux Oiseaux (infected site). We monitored the dynamics of perkinsosis over the course of the experiment at Mundaka and Ile aux Oiseaux. Prevalences were high (>70%), and intensities were around 105 cells g-1 wet gills at Ile aux Oiseaux, and 106 cells g-1 at Mundaka. No significant differences in prevalence or intensity were observed over time. A 2 yr field growth experiment of tagged-recaptured clams was performed to determine individual clam growth rate, condition index (CI), and Perkinsus spp. infection intensity. Clams were collected at Ile aux Oiseaux and transplanted to Arguin. The growth rate was always significantly and negatively correlated with Perkinsus spp. infection, and positively correlated with CI. CI and Perkinsus spp. infection explained 19% and 7% of the variability of the growth rate at Mundaka and Ile aux Oiseaux, respectively. In experimental clams at Arguin, P. olseni infection explained 26% of the variability of the growth rate at the lower tidal level. Our results suggest that at a concentration of between 105 and 106 cells g-1, perkinsosis affects the physiological functions of the clams, highlighted by its impact on the growth rate.

  6. Biomarker responsiveness in different tissues of caged Ruditapes philippinarum and its use within an integrated sediment quality assessment

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Gomez, Julia, E-mail: julia.ramosgomez@uca.es [UNITWIN/UNESCO/WiCoP, Departamento de Quimica Fisica, Universidad de Cadiz, Facultad de Ciencias del Mar y Ambientales, Campus Universitario de Puerto Real, 11510 Puerto Real, Cadiz (Spain); Coz, Alberto; Viguri, Javier R. [Dpto. Ingenieria Quimica y Quimica Inorganica, ETSIIT, Universidad de Cantabria, Avda. los Castros, s/n 39005 Santander (Spain); Luque, Angel [Departamento de Biologia, Universidad de Las Palmas de Gran Canaria, 35017 Las Palmas de Gran Canaria, Gran Canaria, The Canary Islands (Spain); Martin-Diaz, M. Laura [UNITWIN/UNESCO/WiCoP, Departamento de Quimica Fisica, Universidad de Cadiz, Facultad de Ciencias del Mar y Ambientales, Campus Universitario de Puerto Real, 11510 Puerto Real, Cadiz (Spain); Centro Andaluz de Ciencia y Tecnologia Marinas (CACYTMAR), Universidad de Cadiz, Campus Universitario de Puerto Real, 11510 Puerto Real, Cadiz (Spain); DelValls, T. Angel [UNITWIN/UNESCO/WiCoP, Departamento de Quimica Fisica, Universidad de Cadiz, Facultad de Ciencias del Mar y Ambientales, Campus Universitario de Puerto Real, 11510 Puerto Real, Cadiz (Spain)

    2011-07-15

    Biomarkers comprising activities of biotransformation enzymes (ethoxyresorufin-O-deethylase -EROD-, dibenzylfluorescein dealkylase -DBF-, glutathione S-transferase -GST), antioxidant enzymes (glutathione reductase -GR- and glutathione peroxidase -GPX), lipid peroxidation -LPO- and DNA strand breaks were analyzed in the clam Ruditapes philippinarum caged at Cadiz Bay, Santander Bay and Las Palmas de Gran Canaria (LPGC) Port (Spain). Sediments were characterized. Digestive gland was the most sensitive tissue to sediment contamination. In Cadiz Bay, changes in LPO regarding day 0 were related with metals. In LPGC Port, DBF, EROD, and GST activity responses suggested the presence of undetermined contaminants which might have led to DNA damage. In Santander Bay, PAHs were related with EROD activity, organic and metal contamination was found to be associated with GR and GST activities and DNA damage presented significant (p < 0.05) induction. R. philippinarum was sensitive to sediment contamination at biochemical level. Biomarkers allowed chemical exposure and sediment quality assessment. - Highlights: > Ruditapes philippinarum is sensitive to sediment contamination at biochemical level. > Digestive gland biomarkers showed the best correlations with sediment contaminants. > Presence of potentially toxic chemicals not analyzed in this research was unmasked. > Multivariate analysis allowed the identification of toxic xenobiotic and possible sources. > Inner area of Santander Bay presented the highest sediment toxicity. - Integration of Ruditapes philippinarum biomarker results and sediment chemistry distinguished xenobiotic exposure and sediment toxicity in coastal areas of Spain.

  7. Effects of depuration on the element concentration in bivalves: Comparison between sympatric Ruditapes decussatus and Ruditapes philippinarum

    Science.gov (United States)

    Freitas, R.; Ramos Pinto, L.; Sampaio, M.; Costa, A.; Silva, M.; Rodrigues, A. M.; Quintino, V.; Figueira, E.

    2012-09-01

    Organisms living in coastal ecosystems are frequently subjected to anthropogenic pressures such as metals. Metals, especially those not required for metabolic activity (e.g. mercury, lead and cadmium) can be toxic even at quite low concentrations not only to organisms that accumulate them, but also to their consumers. Throughout the world, Ruditapes decussatus and Ruditapes philippinarum have been successfully commercialised for human consumption and for monitoring environmental conditions such as contamination. These two clam species share similar habitats and requirements, successfully competing both in the natural environment and in aquaculture farms. Because differences in metal accumulation may exist between R. decussatus and R. philippinarum, different risks to public health may overcome as well as distinct ecological implications. The effect of depuration on the metal burden and biochemical status of both clams species may also diverge and since the information available is subjective and scarce, the aims of the present study were to: 1) assess the total metal accumulation and intracellular partitioning, at natural conditions, in the two clam species collected at the same site; 2) evaluate the effect of depuration as a mean of reducing the levels of distinct elements, assessing also the effect of depuration time (2 and 7 days); 3) investigate the efficiency of depuration by biochemical status of the two bivalve species, evaluating changes in lipid peroxidation and activity of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and of glutathione S-transferase (GST). Metal chelation by metallothioneins (MTs) was also determined. The results obtained showed that concentration of elements in clams was low, presenting very similar concentration levels for all elements. The present work further demonstrated that the total element concentration decreased in the shorter depuration period (2 days) and that R. decussatus and R. philippinarum partitioned

  8. Analysis of trace elements in the shells of short-necked clam Ruditapes philippinarum (Mollusca: Bivalvia) with respect to reconstruction of individual life history

    Energy Technology Data Exchange (ETDEWEB)

    Arakawa, Jumpei; Sakamoto, Wataru [Division of Applied Biosciences, Graduate School of Agriculture, Kyoto Univ., Kyoto (Japan)

    1998-07-01

    Strontium (Sr) concentration in the shells of short-necked clams collected at different locations (Shirahama, warm area and Maizuru, cold area, Japan) was analyzed by two methods, PIXE and EPMA. The Sr concentration of external surface of shell umbo, which was made during short term at early benthic phase, was analyzed by PIXE, and was ranged from 1000 to 3500 ppm for individuals. The Sr concentration of clams collected at Shirahama showed positive correlation with shell length (SL) in individuals with SL < 31 mm, whereas clams collected at Maizuru did not show significant correlation. This result may be caused from the difference of the spawning seasons between two areas. The Sr concentration of cross section of shell umbo, which develops thicker continuously during their life to form faint stratum structure, was analyzed by EPMA along the line across the stratum structure. Some surges and long term waving patterns of the Sr concentration were observed. These results suggest that the life histories of individual clams could be recorded in the shell umbo cross sections as variations of trace elements and analyses of trace elements could clarify the histories of individual clams. (author)

  9. Isolation, purification and antibacterial activity of lectin from Manila clam Ruditapes philippinarum%菲律宾蛤仔凝集素的分离纯化及抑菌活性研究

    Institute of Scientific and Technical Information of China (English)

    李伟; 陈文; 佟长青; 孔亮; 曲敏; 谭成玉; 金桥; 李丹彤

    2012-01-01

    采用Cellulose DE52离子交换层析、Sephadex G- 100分子筛层析及TSK G3000PWXL凝胶色谱柱HPLC从菲律宾蛤仔Ruditapes philippinarum中分离纯化出具有N-乙酰半乳糖酰胺(N- acetyl- D- galactosamine,GaINAc)和猪胃黏蛋白(Mucin from porcine stomach,PSM)特异性的菲律宾蛤仔凝集素(简称为MCL-T).SDS-PAGE分析结果表明,MCL-T的相对分子量为148000,含有62000和36000的亚基.抑菌试验结果表明,MCL-T对金黄色葡萄球菌Staphylococcus aureus和枯草芽孢杆菌Bacillus subtilis有较高的抑菌活性.对MCL-T中Trp残基、-S-S-、-SH以及Tyr残基进行化学修饰后,MCL-T对金黄色葡萄球菌的抑菌活性丧失;对其-S-S-进行化学修饰后,MCL-T对枯草芽孢杆菌的抑菌活性影响不大,而对其-SH、Trp残基和Tyr残基进行化学修饰后,MCL-T对枯草芽孢杆菌的抑菌活性丧失.研究表明,MCL-T 肽链上的氨基酸残基状态与其抑菌活性有关.%A N-acetyl-D-galactosamine (GalNAc)-/mucin from porcine stomach (PSM) -specific lectin (MCL -T) was purified from Manila clam Ruditapes philippinarum using a combination of ion exchange on Cellulose DE52 and gel filtration on Sephadex G-100 and HPLC on TSK-GEL G3000PWXL. Molecular weight of the MCL-T was determined by SDS-PAGE to be 148 000, containing two kinds of subunits, 62 000 and 36 000. The MCL-T was found to show the antibacterial activities against Staphylococcus aureus and Bacillus subtilis. The antibacterial activities to Staphylococcus aureus was found to be disappeared in the MCL-T in which tryptophan residues, -S-S-, -SH and tyrosine residues were chemically modified. The chemical modification of -S-S- in the MCL-T led to less effects on the antibacterial activities against Bacillus subtilis, but the chemical modification of its -SH, tryptophan residues and tyrosine residues resulted in losing antibacterial activities against Bacillus subtilis. The findings indicate that the patterns of the MCL-T amino acid

  10. 菲律宾蛤仔凝集素抑菌机制的研究%Antibacterial mechanism of short-neck clam Ruditapes philippinarum lectin(MCL-T)

    Institute of Scientific and Technical Information of China (English)

    佟长青; 李琦; 曲敏; 金桥; 李伟

    2014-01-01

    The effects of short-neck clam Ruditapes philippinarum lectin( MCL-T) on respiration, and synthesis of total DNA, total RNA and soluble proteins in bacteria Staphylococcus aureus and Bacillus subtilis, and reaction of MCL-T with out membrane proteins ( OMP) of S. aureus and RNase activity of S. aureus were studied by solid phase assay to elucidate antibacterial mechanism of MCL-T. The MCL-T was shown to inhibit pentose phosphate pathway ( HMP) in respiratory metabolism of the bacteria. The contents of total DNA, total RNA and soluble pro-teins were decreased in both bacteria incubated with MCL-T with increase in concentrations of MCL-T. The solid phase assay revealed that MCL-T binding to out membrane proteins ( OMP) was concentration-dependent and in-hibited by PSM or GalNAc with RNase activity. The findings indicated that MCL-T inhibited the growth of the two bacteria by respiration inhibition, and the antibacterial activities of MCL-T were related to its domains of binding to OMP and to RNase activity.%通过分析菲律宾蛤仔Ruditapes philippinarum凝集素( MCL-T)对细菌的呼吸代谢及细菌中总DNA、总RNA和可溶性蛋白合成的影响,以及MCL-T与金黄色葡萄球菌膜蛋白( OMP)的相互作用及其核酸酶( RNase)活性,研究了MCL-T的抑菌机制。结果表明: MCL-T具有抑制金黄色葡萄球菌Staphylococcus au-reus和枯草芽孢杆菌Bacillus subtilis代谢过程中的磷酸戊糖途径( HMP); MCL-T与金黄色葡萄球菌或枯草芽孢杆菌共同培养时,随着MCL-T质量浓度的增加,金黄色葡萄球菌或枯草芽孢杆菌中的总 DNA、总RNA和可溶性蛋白含量均呈下降趋势;固相吸附测试表明, MCL-T可与金黄色葡萄球菌膜蛋白结合,两者的结合具有浓度依赖关系,该结合位点受N-乙酰-D-半乳糖酰胺( N-acetyl-D-galactosamine, GalNAc)及猪胃黏蛋白(Mucin from porcine stomach, PSM)的抑制, MCL-T具有RNase活性。研究表明, MCL-T通过抑制细菌的呼吸代

  11. Interactive effects of metal contamination and pathogenic organisms on the introduced marine bivalve Ruditapes philippinarum in European populations

    Energy Technology Data Exchange (ETDEWEB)

    Paul-Pont, Ika, E-mail: i.paulpont@epoc.u-bordeaux1.f [Universite Bordeaux 1, UMR 5805 CNRS, Station Marine d' Arcachon, place du Dr. Peyneau, Arcachon 33120 (France); Montaudouin, Xavier de; Gonzalez, Patrice; Jude, Florence; Raymond, Natalie [Universite Bordeaux 1, UMR 5805 CNRS, Station Marine d' Arcachon, place du Dr. Peyneau, Arcachon 33120 (France); Paillard, Christine [Universite de Bretagne Occidentale-IUEM, LEMAR UMR 6539 CNRS, Place Nicolas Copernic, Technopole Brest Iroise, 29280 Plouzane (France); Baudrimont, Magalie [Universite Bordeaux 1, UMR 5805 CNRS, Station Marine d' Arcachon, place du Dr. Peyneau, Arcachon 33120 (France)

    2010-11-15

    In natural environment, marine organisms are concomitantly exposed to pollutants and multiple disease agents resulting in detrimental interactions. The present study evaluated interactive effects of metal contamination (cadmium) and pathogenic organisms (trematode parasites Himasthla elongata and pathogenic bacteria Vibrio tapetis) singularly and in combination on the bivalve Ruditapes philippinarum, an introduced species to Europe, under laboratory controlled conditions. After 7 days, metal bioaccumulation and pathogen load were analyzed as well as metallothionein (MT) response and hemocyte concentrations and activities. Results showed that infection by opportunistic pathogens affects metal accumulation, leading to maximal Cd accumulation in co-infected clams. Among stressors only V. tapetis induced significant effects on immune parameters whereas a particular interaction 'trematode-bacteria' was shown on MT responses. Despite low trematode infection in agreement with the resistant status of R. philippinarum to these macroparasites, significant interaction with bacteria and metal occurred. Such results highlight the necessity of taking pathogens into account in ecotoxicological studies. - Co-infection by opportunistic pathogens affects metal accumulation and some defense-related activities in the Manila clam Ruditapes philippinarum.

  12. Combined effects of seawater acidification and salinity changes in Ruditapes philippinarum.

    Science.gov (United States)

    Velez, Catia; Figueira, Etelvina; Soares, Amadeu M V M; Freitas, Rosa

    2016-07-01

    Due to human activities, predictions for the coming years indicate increasing frequency and intensity of extreme weather events (rainy and drought periods) and pollution levels, leading to salinity shifts and ocean acidification. Therefore, several authors have assessed the effects of seawater salinity shifts and pH decrease on marine bivalves, but most of these studies evaluated the impacts of both factors independently. Since pH and salinity may act together in the environment, and their impacts may differ from their effects when acting alone, there is an urgent need to increase our knowledge when these environmental changes act in combination. Thus, the present study assessed the effects of seawater acidification and salinity changes, both acting alone and in combination, on the physiological (condition index, Na and K concentrations) and biochemical (oxidative stress related biomarkers) performance of Ruditapes philippinarum. For that, specimens of R. philippinarum were exposed for 28days to the combination of different pH levels (7.8 and 7.3) and salinities (14, 28 and 35). The results obtained showed that under control pH (7.8) and low salinity (14) the physiological status and biochemical performance of clams was negatively affected, revealing oxidative stress. However, under the same pH and at salinities 28 and 35 clams were able to maintain/regulate their physiological status and biochemical performance. Moreover, our findings showed that clams under low pH (7.3) and different salinities were able to maintain their physiological status and biochemical performance, suggesting that the low pH tested may mask the negative effects of salinity. Our results further demonstrated that, in general, at each salinity, similar physiological and biochemical responses were found in clams under both tested pH levels. Also, individuals under low pH (salinities 14, 28 and 25) and exposed to pH 7.8 and salinity 28 (control) tend to present a similar response pattern. These

  13. 汉沽养殖菲律宾蛤仔突发性死亡原因调查及分析%The Causative Survey of Sudden Death of Manila Clam Ruditapes philippinarum Cultured in Hangu,Tianjin

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    Manila clam Ruditapes philip pinarum ,sowing in Hangu shallow sea ,occurred serious death with the mortality as high as 86 .2% ,and the grow th was slow from September to October in 2012 .The survey showed that (1)mortality of clams increased with increase in stocking density ;(2)heavy metals , petroleum hydrocarbons and other chemical factors in the seawater and sediments were not excessive ;(3) chlorophyll concentration and primary production were significantly lower from June to August .A large number of mussels Musculus senhousei occurred in mid-June ,and disappeared from September to October , when clams death seriously .The cause of this death in clams was speculated that :the M .senhousei existed in surface sediments competed for food and dissolved oxygen with clams ;mass byssus network impacted clams for feeding and breathing .In addition ,the lower primary production exacerbated the death of the clams .%  2012年9—10月,汉沽浅海底播菲律宾蛤仔发生大规模死亡,死亡率最高达86.2%,同时生长缓慢。调查结果显示,蛤仔死亡率随养殖密度增大而升高;海水和沉积物中重金属、石油烃等化学因子均未超标;6—8月叶绿素含量及初级生产力明显偏低;6月中旬出现寻氏肌蛤,9—10月减少、消失,同时蛤仔出现大规模死亡。推测蛤仔死亡原因为底质表层的寻氏肌蛤与蛤仔争夺近底海水中的饵料和溶氧,并通过足丝网络影响蛤仔的摄食及呼吸。较低的海域初级生产力也进一步加剧了蛤仔的死亡。

  14. Study of the Isolation and Purification of Antioxidative Peptides from Short Necked Clam,Ruditapes Philippinarum%菲律宾蛤仔酶解寡肽的分离及体外抗氧化作用研究

    Institute of Scientific and Technical Information of China (English)

    杨永芳; 杨最素; 丁国芳; 郁迪; 黄芳芳

    2011-01-01

    Objective:In order to get products with antioxidant activity from Ruditapes philippinarum.Methods:Four proteases (pepsin, trypsin, papain, alcalase) were applied to hydrolyze the R.philippinarum.The antioxidative activity of the fractions against the hydroxyl radical produced by H2O2/Fe2+ was determined in vitro.Ultrafiltration and anionexchange chromatography and reversed - phase high - performance liquid chromatography ( RP - HPLC) were performed to separate and purify the antioxidant peptides.Results:Hydrolysate with trypsin had the highest antioxidant activity and was fractionated by ultrafiltration.Three fractions ( < 3KDa, 3 ~ 5KDa, and > 5KDa) were separated.Below 3KDa fraction, which exhibited the highest antioxidative activity, was further purified using anion - exchange and reverse phase high performance liquid chromatography.An antioxidative peptide was isolated and its clearance rate of hydroxyl radical and reducing power were higher than vitamin C.The purified peptide sequences with a molecular weight of 607.6Da was identified as Asp - Trp - Pro - His.Conclusion: Products hydrolyzed by trypsin from R.philippinarum exhibited the best antioxidant activity among all proteases selected, and could be isolated and purified by the methods of ultrafiltration and anion.-exchange chromatography and RP- HPLC.%目的:研究菲律宾蛤仔酶解寡肽的制备方法及其抗氧化活性.方法:选用胃蛋白酶、胰蛋白酶、木瓜蛋白酶、碱性蛋白酶等4种蛋白酶分别对菲律宾蛤仔进行酶解,通过对羟自由基的清除作用来考查各酶解物的抗氧化活性;经超滤、DEAE-SepharoseFF阴离子交换、反相高效液相色谱C18分离制备寡肽,并测定其羟自由基清除率和氧化还原力.结果:胰蛋白酶酶解寡肽清除羟自由基能力最强;经超滤后,3KDa以下的组分羟自由基清除率最高;将该组分纯化后,最终得到1个寡肽,该肽的分子量为607.6KDa,氨基

  15. Manila clam Venerupis philippinarum as a biomonitor to metal pollution

    Institute of Scientific and Technical Information of China (English)

    WU Huifeng; JI Chenglong; WANG Qing; LIU Xiaoli; ZHAO Jianmin; FENG Jianghua

    2013-01-01

    The Manila clam Venerupis philippinarum is a good biomonitor/bioindicator to marine metal pollution and is frequently used in aquatic toxicology.Two dominant pedigrees (white and zebra) of clam are distributed in the Bohai Sea; however,little attention has been paid to potential biological differences between these two pedigrees.In this study,we tested the sensitivity of both pedigrees to marine metal (cadmium and zinc) pollution biomonitoring and marine environmental toxicology.Results demonstrate significant biological differences in gills of white and zebra clams based on metabolic profiles and antioxidant enzyme activities.In addition,we found that hypotaurine,malonate and homarine were relatively high in white clam gills,while alanine,arginine,glutamate,succinate,4-aminobutyrate,taurine and betaine were high in zebra clam gills.Zebra clam gills were also more sensitive to a mixture of Cd and Zn,as shown by antioxidant enzyme activities and metabolic profiles,but white clam gills could accumulate more Zn.Therefore,we suggest that the white pedigree can be used as a biomonitor to marine Zn pollution,whereas the zebra pedigree can be used for toxicology studies on Cd and Zn mixed pollution.

  16. mRNA differential display on gene expression in settlement metamorphosis process of Ruditapes philippinarum larvae

    Institute of Scientific and Technical Information of China (English)

    Lu Sumin; Bao Zhenmin; Hu Jingjie; Hu Xiaoli; Mu Chunhua; Fang Jianguang

    2008-01-01

    The mRNA differential display (DDRT-PCR) technique was adopted to find out the genes related to settlement metamorphosis development process of Ruditapes philippinarum larvae.In this study, we have obtained three hundred and forty-six amplification bands in total from pedivehger larvae, veliger larvae,eye spot larvae and post-larvae.Sixty-five out of three hundred and forty-six bands are distinctly differential display from band pattern, which can be put into four groups, standing for different expression characters.Sixteen differential display bands were cloned, sequenced and analyzed and nine different sequences are obtained in the study.Three sequences have higher similarity to the eDNAs deposited in database and three are very similar to the rDNA of other species, considered as the rDNA of Ruditapes philippinarum.The rest three sequences are found to be novel sequences after analyzed.Their accession numbers are AY916799, AY916798, and AY916797 respectively.We thought the novel sequences are possibly relevant to the early embryo development of Ruditapes philippinarum larvae and can provide some fundamental understandings that are helpful for the improvement of scallop seed raising industry.

  17. Research on heavy metals in Ruditapes philippinarum and soda industry wastes

    Institute of Scientific and Technical Information of China (English)

    ZHU Xiaobin; XU Weihai; WANG Xinting; HUANG Xinping; DENG Liping; KANG Xinglun; JIANG Zhigang; MA Xuli

    2005-01-01

    Heavy metals pollution in Jiaozhou Bay was studied in Ruditapes. philippinarum, a bioindicator of seawater pollution. Heavy metals in soda industry wastes "white mud" were also studied. Comparison of microwave digestion method with general digestion method revealed that microwave digestion is superior to general digestion in precision, recovery, digestion speed and efficiency, etc. Cd concentration in Hongdao R.philippinarum samples exceeded the national standard by 0.046 mg/kg, that of Yinghai sample by 0.02 mg/kg,and that of Hongshiya sample by 0.22 mg/kg. Sample Pb concentration in Hongshiya was found to exceed the national standard by 0.02 mg/kg. However the heavy metals concentration in R. philippinarum near the Qingdao Alkaline Factory was complied with the standard. This was proved by Penaeus chinensis culture experiment.Therefore, the possible contamination source may come from other land areas.

  18. Effect of heavy metals (Cu, Cd and Pb) on aspartate and alanine aminotransferase in Ruditapes philippinarum (Mollusca: Bivalvia)

    Energy Technology Data Exchange (ETDEWEB)

    Blasco, J.; Puppo, J. [Instituto de Ciencias Marinas de Andalucia, Campus Univ. Rio S. Pedro, 11510 Puerto Real, Cadiz (Spain)

    1999-02-01

    The accumulation of cadmium, copper and lead and their effects on aspartate and alanine aminotransferases in digestive gland, gills, foot and soft body in the clam Ruditapes philippinarum were examined. The animals were exposed to different concentrations: Cd (200-600 {mu}g{center_dot}l{sup -1}), Pb (350-700 {mu}g{center_dot}l{sup -1}) and Cu (10-20 {mu}g{center_dot}l{sup -1}) for 7 days. The highest concentrations were found in digestive gland for cadmium and copper, and in gills for lead, and the lowest values were observed in the foot. Aspartate aminotransferase activity (AST), in general, was not inhibited by cadmium, lead or copper during the exposure. Only in clams exposed to cadmium (600 {mu}g{center_dot}l{sup -1}, 7 days) and copper (20 {mu}g{center_dot}l{sup -1}, 5 days) were observed significant differences (P<0.05) in foot and gills, respectively, with respect to control. In the case of alanine aminotransferase activity (ALT), significant differences were observed for cadmium and lead in treated animals with respect to control. With regard to copper, a decrease in ALT was observed in gills and foot exposed to 20 {mu}g{center_dot}l{sup -1}. A significant correlation (P<0.05) was observed between ALT and metal accumulation for cadmium, copper and lead in gills. In the case of soft body, only cadmium and lead showed a significant correlation. In summary, R. philippinarum can be considered a bioindicator species for cadmium and lead accumulation and ALT could be useful as biomarker of sublethal stress for these metals in soft tissues and gills. Only gills can be considered an adequate target tissue for copper. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  19. Observations on shell growth and morphology of the bivalve Ruditapes philippinarum

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The bivalve Ruditapes philippinarum is not only one of the main mollusc species in the west Pacific Ocean, but also one of the main species for aquaculture in China. Knowledge of growth of the R. philippinarum shell will improve our understanding of the shell as an environmental archive. It is also useful for the aquaculture of R. philippinarum. In this research, a hanging box culture method was introduced in the culture of R. philippinarum. The bivalves were cultured for 126 days, from March 31 to August 3, 2002. The average growth rates of shell width, height, and thickness were 0.069, 0.046, and 0.032 mm/d, respectively. The mean increase of average individual wet mass was 0.028 g/d. The largest growth rates of both shell and average individual wet mass occurred in June, indicating that water temperature and bivalve reproduction were 2 important factors. The shell morphology underwent significant changes with shell growth. The ratio of height to thickness (value of B/C) shifted 1.58 in the first 60 days to 1.54 in the last 30 days, which was resulted from the change in major shell growth direction. Periodic changes in the B/C ratio led to corrugated shell form, which could be used to determine the age of the shell.

  20. Transcriptional Responses of Glutathione Transferase Genes in Ruditapes philippinarum Exposed to Microcystin-LR

    Directory of Open Access Journals (Sweden)

    Bruno Reis

    2015-04-01

    Full Text Available Glutathione Transferases (GSTs are phase II detoxification enzymes known to be involved in the molecular response against microcystins (MCs induced toxicity. However, the individual role of the several GST isoforms in the MC detoxification process is still unknown. In this study, the time-dependent changes on gene expression of several GST isoforms (pi, mu, sigma 1, sigma 2 in parallel with enzymatic activity of total GST were investigated in gills and hepatopancreas of the bivalve Ruditapes philippinarum exposed to pure MC-LR (10 and 100 µg/L. No significant changes in GST enzyme activities were found on both organs. In contrast, MC-LR affected the transcriptional activities of these detoxification enzymes both in gills and hepatopancreas. GST transcriptional changes in gills promoted by MC-LR were characterized by an early (12 h induction of mu and sigma 1 transcripts. On the other hand, the GST transcriptional changes in hepatopancreas were characterized by a later induction (48 h of mu transcript, but also by an early inhibition (6 h of the four transcripts. The different transcription patterns obtained for the tested GST isoforms in this study highlight the potential divergent physiological roles played by these isoenzymes during the detoxification of MC-LR.

  1. 菲律宾蛤仔酶解多肽抗前列腺癌DU-145细胞的活性研究%Study on Antiproliferative Activity of Ruditapes philippinarum Hydrolysate on Human Prostate Cancer DU-145 Cell

    Institute of Scientific and Technical Information of China (English)

    李连军; 徐律; 杨最素; 丁国芳; 孙瑜

    2013-01-01

    [Objective] To study Philippines clam enzymolysis peptide on prostate cancer DU-145 cells proliferation activity in vitro.[Method] Digestive enzyme was used to enzymolysis the Philippine clam guts,3 kD molecular weight cut-off membranes were used to fractionate the Ruditapes philippinarum hydrolysate.The anti-proliferation activity and the early apoptosis of Ruditapes philippinarum peptides in vitro were detected by MTT,inverted microscope and AO/EB double staining respectively.[Result] Determined by MTT method,different concentration of peptides to DU-145 cells had obvious growth inhibition.Cell apoptosis morphological feature was observed under AO/EB double staining and inverted microscope.[Conclusion] Ruditapes philippinarum under 3 kD enzyme solution of molecular weight with inhibition of DU-145 cells growth,induce prostate cancer cells apoptosis,and a concentration and time dependence.%[目的]探讨菲律宾蛤仔酶解多肽抗人前列腺癌DU-145细胞增殖的活性.[方法]对菲律宾蛤仔内脏进行酶解,经超滤截取3 kD以下的多肽,应用MTT法、倒置显微镜观察和AO/EB染色等方法检测其体外抗DU-145细胞的活性.[结果]MTT法检测结果表明不同浓度的多肽对DU-145细胞有明显的生长抑制作用.通过倒置显微镜观察和AO/EB荧光双染观察到DU-145细胞出现细胞凋亡的形态学特征.[结论]菲律宾蛤仔3 kD以下的多肽具有抑制DU-145细胞生长,呈浓度和时间依赖性,并诱导细胞凋亡作用.

  2. 蛤仔橙色和白色背景壳色的遗传分析及杂种优势的研究%Genetic analysis of shell color and heterosis of growth and survival for Manila clam Ruditapes philippinarum

    Institute of Scientific and Technical Information of China (English)

    梁健; 董克逊; 闫喜武; 霍忠明; 吴云霞; 杨凤

    2014-01-01

    The 2í2 diallel cross of different shell color for Manila clam Ruditapes philippinarumstrains, two self-fertilized groups ( OO, WW) and two hybrid groups ( OW, WO) were conducted using orange strain ( O) with or-ange shell color and white strain ( W ) with white shell color to investigate the heterosis of growth, survival, meramorphosis and shell color determinism for offsprings. The results showed the positive single-parents growth heterosis of WO was observed in all stages, the same as OW expected the juvenile stage. The hybrid groups own the certain degree mid-parents growth heterosis. There were strong middle and single parent survival heterosis in hybrid groups. On metamorphic stage, the positive heterosis of metamorphosis was observed. In a word, the heterosis of WO was larger than that OW. The egg origin ( maternal) effects were the main factor influencing heterosis of growth and survival at all of stages. The shell color segregation ratio ( orange :white ) of self-fertilized group for orange strain was 3:1, and the hybrid groups was 1:1. The results followed the mendel's law, and it is suggested that or-ange be dominant to white. Shell color was controlled by simple genetic, and was not located at the same homolo-gous chromosomes with control shell surface pattern or banding genetic. There was no gene linkage between shell color and shell surface pattern or banding genetic.%以海洋橙品系( O)和珍珠白品系( W)蛤仔Ruditapes philippinarum为试验材料,采用双列杂交方法建立自交组OO、 WW和杂交组OW、 WO,研究了子一代蛤仔在不同发育时期生长、存活、变态的杂种优势及壳色遗传机制。结果表明:杂交组WO获得了一定程度上的单亲生长优势,杂交组OW在浮游期和变态期表现出生长优势,在稚贝期却表现出生长劣势,但正反交组总体上获得了一定程度的中亲生长优势;在存活率方面,正反交组的中亲存活优势和杂交组WO的单亲存活优势均

  3. Occurrence of diarrhetic shellfish poisoning (DSP) toxins in clams (Ruditapes decussatus) from Tunis north lagoon.

    Science.gov (United States)

    Armi, Zina; Turki, Souad; Trabelsi, Elbahri; Ceredi, Alfiero; Riccardi, Elena; Milandri, Anna

    2012-08-01

    The main diarrhetic shellfish toxins, okadaic acid (OA) and dinophysistoxin-1, 2 (DTX-2, 2) were detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS) as pyrenacyl esters in clams (Ruditapes decussatus) collected in Tunis north lagoon from January 2007 to June 2008. Sample analyses by LC-MS/MS displayed OA and related congeners (DTX-2, 2) with a highest detected level of 21 μg OA eq/kg shellfish meat for the samples of January 2007. Nevertheless, all samples were MBA negative. During the study period, potentially toxic dinoflagellate Dinophysis sacculus was recorded all year, blooming at different times. Highest concentrations were recorded during January 2007 with 4.6 × 10(4) cells per liter and 4.10(4) cells per liter in the northern and southern districts, respectively. Results show that there is no significant correlation between D. sacculus densities in water column and diarrhetic shellfish poisoning (DSP) toxins concentrations unregistered in clams. These data reveal that DSP toxicity in clams of Tunis north lagoon is low according to European regulatory limit (160 μg OA eq/kg shellfish meat). However, a potential threat, in this area, is represented by DSP toxic species as D. sacculus and provides grounds for widen and reinforcing sanitary control of the phycotoxin measures in the region.

  4. Effects of benzo(a)pyrene on differentially expressed genes and haemocyte parameters of the clam Venerupis philippinarum.

    Science.gov (United States)

    Liu, Na; Pan, Luqing; Gong, XiaoLi; Tao, Yanxia; Hu, Yanyan; Miao, Jingjing

    2014-03-01

    In this study a suppression subtractive hybridisation method was employed to identify differentially expressed genes of the clam Venerupis philippinarum exposed to benzo(a)pyrene (BaP). Nineteen known transcripts and seven predicted proteins were found from the subtractive cDNA library of the clam, which could provide more sequence information for further study. Seven of the differentially expressed genes were selected for mRNA expression analysis. Real-time PCR analysis revealed that the expression level of the selected cDNAs of clams was up-regulated to varying degrees by different concentration of BaP. They are suggested as potential molecular biomarkers for polycyclic aromatic hydrocarbons (PAHs) pollution monitoring in aquatic ecosystems. In addition, haemocyte parameters were also measured, and a decrease of total haemocyte counts and suppression of antibacterial and bacteriolytic activities were detected in BaP-stressed clams. We suggest that the modulation of the expression of the selected genes caused by PAHs probably leads to the disturbance of the immune defense of the clam. Meanwhile, the adverse effects of PAHs on haemocyte parameters caused the suppression of the immune defense and susceptibility to infectious diseases. Therefore, it is inferred that PAHs pollutants could interact with components of the immune system and interferes with defense functions of the clam V. philippinarum.

  5. Early replication dynamics of sex-linked mitochondrial DNAs in the doubly uniparental inheritance species Ruditapes philippinarum (Bivalvia Veneridae).

    Science.gov (United States)

    Guerra, D; Ghiselli, F; Milani, L; Breton, S; Passamonti, M

    2016-03-01

    Mitochondrial homoplasmy, which is maintained by strictly maternal inheritance and a series of bottlenecks, is thought to be an adaptive condition for metazoans. Doubly uniparental inheritance (DUI) is a unique mode of mitochondrial transmission found in bivalve species, in which two distinct mitochondrial genome (mtDNA) lines are present, one inherited through eggs (F) and one through sperm (M). During development, the two lines segregate in a sex- and tissue-specific manner: females lose M during embryogenesis, whereas males actively segregate it in the germ line. These two pivotal events are still poorly characterized. Here we investigated mtDNA replication dynamics during embryogenesis and pre-adulthood of the venerid Ruditapes philippinarum using real-time quantitative PCR. We found that both mtDNAs do not detectably replicate during early embryogenesis, and that the M line might be lost from females around 24 h of age. A rise in mtDNA copy number was observed before the first reproductive season in both sexes, with the M mitochondrial genome replicating more than the F in males, and we associate these boosts to the early phase of gonad production. As evidence indicates that DUI relies on the same molecular machine of mitochondrial maternal inheritance that is common in most animals, our data are relevant not only to DUI but also to shed light on how differential segregations of mtDNA variants, in the same nuclear background, may be controlled during development.

  6. Commercial Manila clam ( Tapes philippinarum) culture in British Columbia, Canada: The effects of predator netting on intertidal sediment characteristics

    Science.gov (United States)

    Munroe, Daphne; McKinley, R. Scott

    2007-03-01

    Quantifying risks posed by aquaculture to adjacent coastal ecosystems is necessary to ensure long term stability of coastal systems and the sustainability of industries that exist therein. Research has demonstrated that the use of predator netting in shellfish aquaculture increases sedimentation rates and productivity; here we examine the influence of netting on the west coast of Canada. Changes in percent silt (sediment particles gravel (sediment particles >2 mm), organic and inorganic carbon levels and temperature, and differences in clam populations were monitored on paired netted and non-netted Manila clam ( Tapes philippinarum) plots on four farmed beaches at Baynes Sound, British Columbia in 2003 and 2004. There were no significant differences in the levels of silt ( p = 0.129, n = 8), gravel ( p = 0.723, n = 8), or inorganic carbon ( p = 0.070, n = 8) between netted and non-netted plots. However, the level of organic carbon was significantly higher on netted plots ( p = 0.014, n = 8) and a slight temperature buffering effect of the netting during low-tide events over the period of study. There were significantly more T. philippinarum on netted plots compared to non-netted plots ( p = 0.001, n = 8) and the length frequency distribution of the populations also differed ( p Sound British Columbia, has limited effect on the sediment.

  7. Effect of cadmium in the clam Ruditapes decussatus assessed by proteomic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chora, Suze [University of Algarve, CIMA, Faculty of Marine and Environmental Sciences, Campus de Gambelas, 8000-139 Faro (Portugal); University of Nice-Sophia Antipolis EA 4228 ECOMERS ' Ecosystemes Cotiers Marins et Reponses aux stress' Parc Valrose, BP 71, 06108 Nice cedex 2 (France); Starita-Geribaldi, Mireille [University of Nice-Sophia Antipolis, Laboratory of Oral Microbiology, URE 01., Faculty of Odontology, Pole Universitaire Saint-Jean d' Angely, 24 avenue des Diables Bleus 06357 Nice cedex 4 (France); Guigonis, Jean-Marie [University of Nice-Sophia Antipolis, Plateforme Bernard Rossi - Proteome Metabolome IFR50, Nice, F-06107 (France); Samson, Michel [University of Nice-Sophia Antipolis, Plateforme Bernard Rossi - Proteome Metabolome IFR50, Nice, F-06107 (France); INSERM, Unite 638, Nice, F-06107 (France); Romeo, Michele [University of Nice-Sophia Antipolis EA 4228 ECOMERS ' Ecosystemes Cotiers Marins et Reponses aux stress' Parc Valrose, BP 71, 06108 Nice cedex 2 (France); Bebianno, Maria Joao, E-mail: mbebian@ualg.pt [University of Algarve, CIMA, Faculty of Marine and Environmental Sciences, Campus de Gambelas, 8000-139 Faro (Portugal)

    2009-10-04

    Cadmium, an environmental stressor due to its toxicity, persistence and accumulation in biota, is widespread in the aquatic environment. Cadmium accumulation kinetics have revealed that Ruditapes decussatus has a high affinity to this metal. Proteomics is an effective tool to evaluate the toxic effects of contaminants. The aim of this study was to investigate the Cd effects in the gill and digestive gland of the sentinel species R. decussatus. Protein expression profiles (PEPs) in the clam tissues exposed to Cd (40 {mu}g l{sup -1}, 21 days) were compared to unexposed ones. Cd induces major changes in tissue-specific protein expression profiles in gill and digestive gland. This tissue dependent response results mainly from differences in Cd accumulation, protein inhibition and/or autophagy. An overall decrease of protein spots was detected in both treated tissues, being higher in gill. Some of the spots more drastically altered after pollutants exposure were excised and nine were identified by micro liquid chromatography tandem mass spectrometry (LC-MS/MS). Proteins identified by homology search in databases included: three proteins (8-fold) up-regulated, one down-regulated, four suppressed and one induced. Cd induces major changes in proteins involved in cytoskeletal structure maintenance (muscle-type actin, adductor muscle actin and {beta}-tubulin), cell maintenance (Rab GDP) and metabolism (ALDH and MCAD, both identified by de novo sequencing) suggesting potential energetic change. They provide a valuable knowledge of Cd effects at biochemical and molecular levels in the gill and digestive gland of R. decussatus.

  8. Glutathione Transferases Responses Induced by Microcystin-LR in the Gills and Hepatopancreas of the Clam Venerupis philippinarum

    Directory of Open Access Journals (Sweden)

    Mariana Carneiro

    2015-06-01

    Full Text Available A multi-method approach was employed to compare the responses of Glutatione Transferases (GSTs in the gills and hepatopancreas of Venerupis philippinarum to microcystins (MCs toxicity. In this way, using the cytosolic fraction, the enzymatic activity of GSTs, superoxide dismutase (SOD, serine/threonine protein phosphatases (PPP2 along with the gene expression levels of four GST isoforms (pi, mu, sigma1, sigma2 were investigated in both organs of the clams exposed for 24 h to 10, 50 and 100 μg L−1 of MC-LR. Cytosolic GSTs (cGSTs from both organs of the high dose exposed clams were purified by glutathione-agarose affinity chromatography, characterized kinetically and the changes in the expression of cGSTs of the gills identified using a proteomic approach. MC-LR caused an increase in GST enzyme activity, involved in conjugation reactions, in both gills and hepatopancreas (100 μg L−1 exposure. SOD activity, an indicator of oxidative stress, showed significantly elevated levels in the hepatopancreas only (50 and 100 μg L−1 exposure. No significant changes were found in PPP2 activity, the main target of MCs, for both organs. Transcription responses revealed an up-regulation of sigma2 in the hepatopancreas at the high dose, but no significant changes were detected in the gills. Kinetic analysis evidenced differences between gills of exposed and non-exposed extracts. Using proteomics, qualitative and quantitative differences were found between the basal and inducible cGSTs. Overall, results suggest a distinct role of GST system in counteracting MCs toxicity between the gills and the hepatopancreas of V. philippinarum, revealing different roles between GST isoforms within and among both organs.

  9. Glutathione Transferases Responses Induced by Microcystin-LR in the Gills and Hepatopancreas of the Clam Venerupis philippinarum.

    Science.gov (United States)

    Carneiro, Mariana; Reis, Bruno; Azevedo, Joana; Campos, Alexandre; Osório, Hugo; Vasconcelos, Vítor; Martins, José Carlos

    2015-06-09

    A multi-method approach was employed to compare the responses of Glutatione Transferases (GSTs) in the gills and hepatopancreas of Venerupis philippinarum to microcystins (MCs) toxicity. In this way, using the cytosolic fraction, the enzymatic activity of GSTs, superoxide dismutase (SOD), serine/threonine protein phosphatases (PPP2) along with the gene expression levels of four GST isoforms (pi, mu, sigma1, sigma2) were investigated in both organs of the clams exposed for 24 h to 10, 50 and 100 μg L(-1) of MC-LR. Cytosolic GSTs (cGSTs) from both organs of the high dose exposed clams were purified by glutathione-agarose affinity chromatography, characterized kinetically and the changes in the expression of cGSTs of the gills identified using a proteomic approach. MC-LR caused an increase in GST enzyme activity, involved in conjugation reactions, in both gills and hepatopancreas (100 μg L(-1) exposure). SOD activity, an indicator of oxidative stress, showed significantly elevated levels in the hepatopancreas only (50 and 100 μg L(-1) exposure). No significant changes were found in PPP2 activity, the main target of MCs, for both organs. Transcription responses revealed an up-regulation of sigma2 in the hepatopancreas at the high dose, but no significant changes were detected in the gills. Kinetic analysis evidenced differences between gills of exposed and non-exposed extracts. Using proteomics, qualitative and quantitative differences were found between the basal and inducible cGSTs. Overall, results suggest a distinct role of GST system in counteracting MCs toxicity between the gills and the hepatopancreas of V. philippinarum, revealing different roles between GST isoforms within and among both organs.

  10. Sex-linked mitochondrial behavior during early embryo development in Ruditapes philippinarum (Bivalvia Veneridae) a species with the Doubly Uniparental Inheritance (DUI) of mitochondria.

    Science.gov (United States)

    Milani, Liliana; Ghiselli, Fabrizio; Passamonti, Marco

    2012-05-01

    In most metazoans mitochondria are inherited maternally. However, in some bivalve molluscs, two mitochondrial lineages are present: one transmitted through females (F-type), the other through males (M-type). This unique system is called Doubly Uniparental Inheritance (DUI) of mitochondria. In DUI species, M-type mitochondria have to invade the germ line of male embryos during development, otherwise sperm would transmit F-type mtDNA and DUI would fail. The mechanisms by which sperm mitochondria enter the germ line are still unknown. To address this question, we traced the movement of spermatozoon mitochondria (M-type) in embryos of the DUI species Ruditapes philippinarum by fertilizing eggs with sperm stained with the mitochondrial-specific vital dye MitoTracker Green. As in Mytilus DUI species, in R. philippinarum the distribution of sperm mitochondria follows two different patterns: an aggregated one in which these organelles locate near the first cleavage furrow, and a dispersed one in which sperm mitochondria are scattered. The presence of the two mitochondrial patterns in these taxa, together with their absence in species with Strictly Maternal Inheritance (SMI), confirms that their occurrence is related to DUI. Moreover, a Real-Time qPCR analysis showed that neither M-type nor F-type mitochondria undergo replication boosts in the earliest embryo development. This is the first study on sex-linked mtDNA copy number carried out by qPCR analysis on embryos of a DUI species and the first time the segregation patterns of sperm mitochondria are described in a DUI system other than Mytilus.

  11. Microplastic Ingestion by Wild and Cultured Manila Clams (Venerupis philippinarum) from Baynes Sound, British Columbia.

    Science.gov (United States)

    Davidson, Katie; Dudas, Sarah E

    2016-08-01

    Microplastics, plastic particles Baynes Sound, British Columbia were chosen to examine the microplastic concentrations in wild and cultured Manila clams. Microplastics were isolated using a nitric acid digestion technique and enumerated from 54 clams (27 farmed and 27 non-farmed). Qualitative attributes, such as colour and microplastic type (fiber, fragment, or film) also were recorded. There was no significant difference (F = 1.29; df = 1,4; P = 0.289) between microplastic concentrations in cultured and wild clams. Microplastic concentrations ranged from 0.07 to 5.47 particles/g (from reference beach and shellfish farm clams, respectively). Fibers were the dominant microplastic (90 %); colourless and dark gray fibers were the most common colours observed (36 and 26 %, respectively). Although this indicates that microplastics are definitely present in seafood consumed by humans, shellfish aquaculture operations do not appear to be increasing microplastic concentrations in farmed clams in this region.

  12. Seasonal Variation of Taurine Content in Ruditapes philippinarum%杂色蛤中牛磺酸含量与季节变化的关系

    Institute of Scientific and Technical Information of China (English)

    章骞; 沈建东; 赵雪冰; 张凌晶; 曹敏杰

    2015-01-01

    旨在探明几种常见海洋经济水产品的牛磺酸含量,特别是杂色蛤(Ruditapes philippinarum)中牛磺酸含量随季节变化的规律.以杂色蛤为原料,制备牛磺酸并利用高压液相色谱法分析牛磺酸的纯度.结果发现,几种常见海洋经济水产品中,杂色蛤体内的牛磺酸含量最高,达8.22 g/kg.以此为原料可制备纯度达92.92%的天然牛磺酸.杂色蛤中牛磺酸含量的季节变化规律为:1-4月牛磺酸含量逐渐升高,4-8月逐渐下降,至8月份达最低点,9月后又逐渐回升,牛磺酸含量介于1784.57~ 2519.74 μg/mL之间.而且,牛磺酸含量的季节变化规律与气温变化基本呈反相关关系.

  13. Effect of acclimatization on hemocyte functional characteristics of the Pacific oyster (Crassostrea gigas) and carpet shell clam (Ruditapes decussatus).

    Science.gov (United States)

    Hurtado, Miguel Ángel; da Silva, Patricia Mirella; Le Goïc, Nelly; Palacios, Elena; Soudant, Philippe

    2011-12-01

    Most experimental procedures on molluscs are done after acclimatization of wild animals to lab conditions. Similarly, short-term acclimation is often unavoidable in a field survey when biological analysis cannot be done within the day of sample collection. However, acclimatization can affect the general physiological condition and particularly the immune cell responses of molluscs. Our aim was to study the changes in the hemocyte characteristics of the Pacific oyster Crassostrea gigas and the carpet shell clam Ruditapes decussatus acclimated 1 or 2 days under emersed conditions at 14 ± 1 °C and for 1, 2, 7, or 10 days to flowing seawater conditions (submerged) at 9 ± 1 °C, when compared to hemolymph withdrawn from organisms sampled in the field and immediately analyzed in the laboratory (unacclimated). The hemocyte characteristics assessed by flow cytometry were the total (THC) and differential hemocyte count, percentage of dead cells, phagocytosis, and reactive oxygen species (ROS) production. Dead hemocytes were lower in oysters acclimated both in emersed and submerged conditions (1%-5%) compared to those sampled in the field (7%). Compared to oysters, the percentage of dead hemocytes was lower in clams (0.4% vs. 1.1%) and showed a tendency to decrease during acclimatization in both emersed and submerged conditions. In comparison to organisms not acclimated, the phagocytosis of hemocytes decreased in both oysters and clams acclimated under submerged conditions, but was similar in those acclimated in emersed conditions. The ROS production remained stable in both oysters and clams acclimated in emersed conditions, whereas in submerged conditions ROS production did not change in both the hyalinocytes and granulocytes of oysters, but increased in clams. In oysters, the THC decreased when they were acclimated 1 and 2 days in submerged conditions and was mainly caused by a decrease in granulocytes, but the decrease in THC in oysters acclimated 2 days in emersed

  14. Polymerase chain reaction-restriction fragment length polymorphism analysis of a 16S rRNA gene fragment for authentication of four clam species.

    Science.gov (United States)

    Fernandez, Alicia; García, Teresa; Gonzalez, Isabel; Asensio, Luis; Rodriguez, Miguel Angel; Hernández, Pablo E; Martin, Rosario

    2002-04-01

    Specific identification of four clam species, Ruditapes decussatus (grooved carpet shell), Venerupis pullastra (pullet carpet shell), Ruditapes philippinarum (Japanese carpet shell), and Venerupis rhomboides (yellow carpet shell), was achieved by polymerase chain reaction-restriction fragment length polymorphism analysis of a fragment of the mitochondrial 16S rRNA gene. Amplification of DNA isolated from the foot muscle produced fragments of 511 bp for V. pullastra, 523 bp for R. decussatus, 545 bp for R. philippinarum, and 502 bp for V. rhomboides. The restriction profiles obtained by agarose gel electrophoresis when amplicons were digested with endonucleases BsmAI and BsrI allowed unequivocal identification of the four clam species. This approach would be less costly, simpler, and quicker than conventional sequencing of polymerase chain reaction products followed by detailed comparison of individual sequences, especially when large numbers of samples need to be analyzed.

  15. A microarray-based analysis of gametogenesis in two Portuguese populations of the European clam Ruditapes decussatus.

    Directory of Open Access Journals (Sweden)

    Joana Teixeira de Sousa

    Full Text Available The European clam, Ruditapes decussatus is a species with a high commercial importance in Portugal and other Southern European countries. Its production is almost exclusively based on natural recruitment, which is subject to high annual fluctuations. Increased knowledge of the natural reproductive cycle of R. decussatus and its molecular mechanisms would be particularly important in providing new highly valuable genomic information for better understanding the regulation of reproduction in this economically important aquaculture species. In this study, the transcriptomic bases of R. decussatus reproduction have been analysed using a custom oligonucleotide microarray representing 51,678 assembled contigs. Microarray analyses were performed in four gonadal maturation stages from two different Portuguese wild populations, characterized by different responses to spawning induction when used as progenitors in hatchery. A comparison between the two populations elucidated a specific pathway involved in the recognition signals and binding between the oocyte and components of the sperm plasma membrane. We suggest that this pathway can explain part of the differences in terms of spawning induction success between the two populations. In addition, sexes and reproductive stages were compared and a correlation between mRNA levels and gonadal area was investigated. The lists of differentially expressed genes revealed that sex explains most of the variance in gonadal gene expression. Additionally, genes like Foxl2, vitellogenin, condensing 2, mitotic apparatus protein p62, Cep57, sperm associated antigens 6, 16 and 17, motile sperm domain containing protein 2, sperm surface protein Sp17, sperm flagellar proteins 1 and 2 and dpy-30, were identified as being correlated with the gonad area and therefore supposedly with the number and/or the size of the gametes produced.

  16. First multi-year retrospective study on Vibrio parahaemolyticus and Vibrio vulnificus prevalence in Ruditapes philippinarum harvested in Sacca di Goro, Italy

    Directory of Open Access Journals (Sweden)

    Patrizia Serratore

    2016-11-01

    Full Text Available The present work describes a retrospective study aiming to verify a possible correlation between the environmental conditions (temperature, salinity and dissolved oxygen, the abundance of Vibrio spp., and the prevalence of V. parahaemolyticus and V. vulnificus in the Manila clam R. philippinarum harvested in Sacca di Goro, Emilia-Romagna Region, Northern Italy. On the whole, 104 samples, collected in the period 2007-2015 and submitted to microbiological analyses (isolation and genotyping, have been reconsidered for Vibrio spp. load, V. parahaemolyticus prevalence (total, gene marker toxRP; potentially pathogenic, gene markers tdh and/or trh and V. vulnificus prevalence (total, gene markers vvhA and hsp together with environmental data obtained from the monitoring activity of the Emilia-Romagna Regional Agency for the Prevention, the Environment and the Energy. Environmental data have been processed to calculate the median of each, assessing the seasonal range of seawater temperature (warmer months: April-October, T°C >16.45°C; cooler months November-March, T°C 27 psu, and dissolved oxygen (< or >8.2 mg/L. Total V. vulnificus, total and potentially pathogenic V. parahaemolyticus were present respectively in the 11.5, 29.8 and 6.7% of the samples. The Vibrio spp. load (mean value of 4.69±0.65 log10 colony forming unit g-1 and the prevalence of potentially pathogenic V. parahaemolyticus, were not significantly correlated to the environmental conditions (P>0.05, whereas the prevalence of both total V. vulnificus and total V. parahaemolyticus was significantly higher in the warmer period (P<0.05, without correlation with salinity and dissolved oxygen values (P>0.05.

  17. Perkinsus olseni and P. chesapeaki detected in a survey of perkinsosis of various clam species in Galicia (NW Spain) using PCR-DGGE as a screening tool.

    Science.gov (United States)

    Ramilo, Andrea; Pintado, José; Villalba, Antonio; Abollo, Elvira

    2016-01-01

    A survey on perkinsosis was performed involving 15 locations scattered along the Galician coast (NW Spain) and four clam species with high market value (Ruditapes decussatus, Ruditapes philippinarum, Venerupis corrugata and Polititapes rhomboides). The prevalence of Perkinsus parasites was estimated by PCR using genus-specific primers. The highest percentage of PCR-positive cases for perkinsosis corresponded to clams R. decussatus and V. corrugata, while lower values were detected in R. philippinarum and no case was found in P. rhomboides. The discrimination of Perkinsus species was performed by PCR-RFLP and by a new PCR-DGGE method developed in this study. Perkinsus olseni was identified in every clam species, except in P. rhomboides, using both PCR-DGGE and PCR-RFLP. Additionally, Perkinsus chesapeaki was only detected by PCR-DGGE infecting two Manila clams R. philippinarum from the same location, reporting the first case in Galicia. P. chesapeaki identification was further confirmed by in situ hybridisation assay and phylogenetic analysis of ITS region and LSU rDNA.

  18. Spatial distribution and bioaccumulation patterns in three clam populations from a low contaminated ecosystem

    Science.gov (United States)

    Velez, Cátia; Figueira, Etelvina; Soares, Amadeu; Freitas, Rosa

    2015-03-01

    When consuming bivalves, special concern should be taken to the total element burden. In order to assess this issue the present study aimed to measure the element levels in the sediments of different harvesting areas and relate them with clam accumulation; to assess the elements body burden, their availability for trophic transfer and relate it with total accumulation in clams, comparing the native (Ruditapes decussatus and Venerupis corrugata) and the invasive (Ruditapes philippinarum) species; to evaluate the human risk associated with the consumption of different clam species. The results showed that the element burden in clams does not reflect the sediment contamination and BAF values were higher in the less contaminated areas. Comparison of Maximum Levels (MLs) from international organizations with the concentration of elements in clams showed that As exceeded standard levels. The ingestion of less than 1 Kg per week of clams would result in exceeding the PTWI threshold for As. Furthermore, the results showed that, when comparing to other elements, As and Hg are more easily available to be transferred trophically.

  19. Biochemical compounds' dynamics during larval development of the carpet-shell clam Ruditapes decussatus (Linnaeus, 1758): effects of mono-specific diets and starvation

    Science.gov (United States)

    Matias, Domitília; Joaquim, Sandra; Ramos, Margarete; Sobral, Paula; Leitão, Alexandra

    2011-09-01

    Successful larval growth and development of bivalves depend on energy derived from internal (endotrophic phase) and external (exotrophic phase) sources. The present paper studies survival, growth and biochemical changes in the early developmental stages (from egg to pediveliger) of the clam Ruditapes decussatus in order to characterize the nutritional requirements and the transition from the endotrophic to the exotrophic phase. Three different feeding regimes were applied: starvation and two mono-specific microalgal diets ( Isochrysis aff galbana and Chaetoceros calcitrans). A comparison between fed and unfed larvae highlighted the importance of egg lipid reserves, especially neutral lipids, during a brief endotrophic phase of embryonic development (first 2 days after fertilization). Egg reserves, however, may energetically contribute to the maintenance of larvae beyond the embryonic development. In fed larvae, the endotrophic phase is followed by a mixotrophic phase extending to days 5-8 after fertilization and a subsequent exotrophic phase. Metamorphosis starts around day 20. The intense embryonic activities are supported by energy derived from lipids, mainly from neutral lipids, and the metamorphic activities are supported by energy derived essentially from proteins accumulated during the planktonic phase and depend on the nutritional value of diets. The diet of I. aff galbana proves to be more adequate to R. decussatus larval rearing. The results provide useful information for the successful production of R. decussatus aquaculture.

  20. Cd2+-B[α]P复合污染对菲律宾蛤仔急性毒性和解毒代谢酶活力的影响%COMBINATION EFFECTS OF CADMIUM AND BENZO[α]PYRENE ON ACUTE TOXICITY AND METABOLIC ENZYMES ACTIVITIES OF RUDITAPES PHILIPPINARUM

    Institute of Scientific and Technical Information of China (English)

    王琳; 潘鲁青; 许超群; 刘娜

    2011-01-01

    Cadmium (Cd) is a nonessential element and is potentially highly toxic to human, animal and plant, even at low doses.It accumulates within the bodies of organisms, alters and degrades processes of enzyme activation, causes cell damage and results in organism death.Polycyclic aromatic hydrocarbons (PAHs) are common coastal environmental organic pollutants derived from petroleum, ocean shipping and industry sewage.It is a global problem since these compounds are known to be highly mutagenic and carcinogenic, as well as bioaccumulating and persistent.Heavy metals and their interactions with PAHs frequently occur, and organisms are usually exposed to chemicals in combinations.The clam Ruditapes philippinarum is a main commercial mollusk widely distribute in the coastal area of China.In the present study, R.philippinarum was exposed to Cd, benzo[α]pyrene (BaP) and a mixture of Cd and BaP, as model substances, in order to evaluate the relationship of tissue Cd and BaP actuce toxicity, metabolic parameters such as total reduced glutathione (GSH), glutathione S-transferase (GST) and superoxide dismutase (SOD).The aim of the study was to investigate the interference mechanisms between Cd and BaP, as well as assess the parameters for using as biomarkers of the combined pollution in marine environments.Two-year-old calms [R.philippinarum, average shell length: (43.5 ± 1.7) mm; shell height: (29.4 ± 1.1) mm;mass: (10.7 ± 1.7) g]were collected from the Red Island (Yellow Sea, Qingdao, China).Clams were put in 50 L glass tanks (0.5 L water per clam) and acclimated to photophobic underground laboratory conditions for 10 days in sand-filtered seawater pumped from the Red Island (Yellow Sea, Qingdao, China).The seawater was continuously aerate, and salinity, temperature and pH were maintained at 31 psu, 16.0 ± 0.6 ℃ and 8.1, respectively.The water was renewed every day.The clams were fed with dried powder of Spirulina platensis daily.In the acute experiments, the calms were

  1. An Efficient Method of Noroviruses Recovery from Oysters and Clams

    Institute of Scientific and Technical Information of China (English)

    ZHOU Deqing; MA Liping; ZHAO Feng; YAO Lin; SU Laijin; LI Xinguang

    2013-01-01

    Noroviruses (NoVs) are widespread causes of nonbacterial gastroenteritis.Outbreaks of NoVs caused diseases are commonly ascribed to the consumption of contaminated shellfish.The concentration and RNA extraction of NoVs are crucial steps of detecting NoVs in shellfish.This study aimed to select a simple,rapid and highly efficient recovery method of NoVs detection with real-time RT-PCR.Four methods of recovering GI.3 and GII.4 NoVs from spiked digestive tissues of oysters and clams,respectively,were compared,of them,the method involving proteinase K and PEG 8000 was found the most efficient.With this method,9.3% and 13.1% of GI.3 and GII.4 NoVs were recovered from oysters and 9.6% and 12.3% of GI.3 and GII.4 NoVs were recovered from clams,respectively.This method was further used to detect NoVs in 84 oysters (Crassostrea gigas) and 86 clams (Ruditapes philippinarum) collected from 10 coastal cities in China from Jan.2011 to Feb.2012.The NoVs isolation rates were 10.47% of clams (9/86) and 7.14% of oysters (6/84).All the detected NoVs belonged to genotype GII.The NoVs recovery method selected is efficient for NoVs detection in oysters and clams.

  2. An efficient method of noroviruses recovery from oysters and clams

    Science.gov (United States)

    Zhou, Deqing; Ma, Liping; Zhao, Feng; Yao, Lin; Su, Laijin; Li, Xinguang

    2013-03-01

    Noroviruses (NoVs) are widespread causes of nonbacterial gastroenteritis. Outbreaks of NoVs caused diseases are commonly ascribed to the consumption of contaminated shellfish. The concentration and RNA extraction of NoVs are crucial steps of detecting NoVs in shellfish. This study aimed to select a simple, rapid and highly efficient recovery method of NoVs detection with real-time RT-PCR. Four methods of recovering GI.3 and GII.4 NoVs from spiked digestive tissues of oysters and clams, respectively, were compared, of them, the method involving proteinase K and PEG 8000 was found the most efficient. With this method, 9.3% and 13.1% of GI.3 and GII.4 NoVs were recovered from oysters and 9.6% and 12.3% of GI.3 and GII.4 NoVs were recovered from clams, respectively. This method was further used to detect NoVs in 84 oysters ( Crassostrea gigas) and 86 clams ( Ruditapes philippinarum) collected from 10 coastal cities in China from Jan. 2011 to Feb. 2012. The NoVs isolation rates were 10.47% of clams (9/86) and 7.14% of oysters (6/84). All the detected NoVs belonged to genotype GII. The NoVs recovery method selected is efficient for NoVs detection in oysters and clams.

  3. Identification and molecular cloning of the allergen tropomyosin from Ruditapes philippinarum%菲律宾蛤仔过敏原原肌球蛋白的鉴定与分子克隆

    Institute of Scientific and Technical Information of China (English)

    吕良涛; 蔺海鑫; 高卿; 林洪; 李振兴

    2015-01-01

    目的:了解菲律宾蛤仔中过敏原的情况,对其主要过敏原进行鉴定和分子克隆。方法采用聚丙烯酰胺凝胶电泳和免疫印迹验证原肌球蛋白,双向电泳对蛋白等电点进一步确定。利用差示扫描量热法对蛋白的热性能测定以及蛋白克隆和测序来分析原肌球蛋白。结果菲律宾蛤仔原肌球蛋白的分子量在37 kDa左右,等电点为5.1,热稳定性较强。原肌球蛋白的基因序列全长为855 bp,编码284个氨基酸,对序列进行同源对比,相似性较高。结论本实验证实了原肌球蛋白为菲律宾蛤仔的过敏原,为认识菲律宾蛤仔过敏原提供基础数据。%ABSTRACT:Objective To investigate theRuditapes philippinarum allergen, and identify and clone the main allergens.MethodsTropomyosin was identified by polyacrylamide gel electrophoresis and immunoblotting, and isoelectric point was further analyzed by two dimensional electrophoresis. Thermal stability analysis was determined by differential scanning calorimetry, and tropomyosin was analyzed by cloning and sequencing of proteins. ResultsThe major allergen protein tropomyosin with the molecular weight 37 kDa was extracted. The isoelectric point was 5.1. Thetropomyosin ofR.philippinarumwas stable in the process of thermal treatment. The full-length cDNAs encoding tropomyosin was composed of 855 bp coding for 284 amino acid residues. The similarity of sequence was high through homologous comparison. ConclusionThe tropomyosin is the allergen of R.philippinarum. This research is helpful to provide the basic date to understandR.philippinarumallergen.

  4. First evidence of altered vitellogenin-like protein levels in clam Tapes philippinarum and in cockle Cerastoderma glaucum from the Lagoon of Venice.

    Science.gov (United States)

    Matozzo, Valerio; Marin, Maria Gabriella

    2007-01-01

    Possible xenoestrogenic effects were investigated, for the first time, in two bivalve species from the Lagoon of Venice (Italy): the clam Tapes philippinarum and the cockle Cerastoderma glaucum. Bivalves were collected far from their reproductive phase at the very early stage of gametogenesis (January), and in the pre-spawning period (June) in six sites. Vitellogenin (Vg)-like proteins (a biomarker of exposure to estrogenic compounds) were measured by the alkali-labile phosphate method (ALP), in both haemolymph and digestive gland from males and females (when it was possible to distinguish sex by microscopic observation of gonadal tissue). Haemolymph calcium concentrations (a parameter considered closely related to the presence of Vg-like proteins) and the bivalve condition index (CI) were also measured. In both seasons, bivalves collected at Campalto (near a sewage treatment plant) and Marghera (a highly contaminated area) had higher Vg-like protein levels, particularly in haemolymph, than animals from the other sampling sites. Interestingly, CI had high values in these polluted sites. In June only, Vg-like proteins and Ca(2+) levels in haemolymph exhibited similar trends in both bivalve species at most sampling sites. The responsiveness of bivalves to environmental xenoestrogens was higher in June, allowing better discrimination among sites. The present study demonstrates that animals from highly polluted areas have increased Vg-like protein levels. As endocrine disruption due to exposure to estrogenic compounds may cause fertility reduction, alterations in the sex ratio, and a decrease in reproductive rate, a condition of potential risk for bivalve populations in estuarine areas is highlighted.

  5. Metal and metallothionein distribution in different tissues of the Mediterranean clam Venerupis philippinarum during copper treatment and detoxification.

    Science.gov (United States)

    Santovito, Gianfranco; Boldrin, Francesco; Irato, Paola

    2015-01-01

    Filter feeding animals can accumulate large amount of contaminants in their body through particles filtered from seawater. In particular, copper is interesting since it plays important roles as co-factor of numerous proteins but its toxicity is well established, also because it can readily generate free radicals or oxidize cellular components through their redox activity. Its availability is tightly regulated within cells: it is immediately transferred to metallothionein (MT) that in turn provides efficient and specific mechanisms for its intracellular storage and transport. The aim of this study was to evaluate the acute effect of sublethal copper concentrations in Venerupis philippinarum, by studying the kinetics of copper, zinc (for its interactions at the sites of intake or elimination with the accumulation of other essential and not essential trace metals) and metallothionein accumulation under laboratory conditions. The time-course of metal accumulation/elimination is similar in digestive gland and gills and importantly it is dose-dependent. Both copper and zinc increase slowly within cells, reaching a maximum concentration at the end of the exposure period. During the detoxification period, the metal levels in digestive gland and gills rapidly decrease, with different kinetics in the two tissues. Positive correlations between metallothionein accumulation and copper or zinc concentrations have been verified in both treated groups. The obtained data demonstrated the involvement of MTs in detoxification strategies after a recovery period in clean seawater.

  6. Effects of anthracene on filtration rates, antioxidant defense system, and redox proteomics in the Mediterranean clam Ruditapes decussatus (Mollusca: Bivalvia).

    Science.gov (United States)

    Sellami, Badreddine; Khazri, Abdelhafidh; Louati, Héla; Dellali, Mohamed; Driss, Mouhamed Ridha; Aïssa, Patricia; Mahmoudi, Ezzeddine; Hamouda, Beyrem; Coelho, Ana Varela; Sheehan, David

    2015-07-01

    This study aimed at analyzing the impact of a toxic polyaromatic hydrocarbon (PAH), anthracene (ANT), on Ruditapes decussatus collected from a Tunisian coastal lagoon (Bizerte Lagoon). Filtration rates, several antioxidant enzymes--superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione transferase (GST)--as well as indices of protein oxidation status were determined in various tissues of this bivalve. Specimens were exposed to 100 μg/L of ANT for 2 days. ANT levels were evaluated using HPLC and were detected in the gill and digestive gland at different amounts. ANT exposure altered the behavior of bivalves by changing the siphon movement and decreasing filtration rate significantly. The enzymatic results indicated that ANT exposure affected the oxidative stress status of the gills of R. decussatus. In addition, modification of proteins was detected in the gills using redox proteomics after ANT treatment. Three protein spots were successfully identified by matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF-MS). These proteins can be roughly related to muscle contraction function. In contrast, no significant modification of enzymatic and protein responses was detected in the digestive gland after ANT treatment. These data demonstrate that combined behavioral and biochemical analyses are a powerful tool to provide valuable insights into possible mechanisms of toxicity of anthracene in R. decussatus. Additionally, the results highlight the potential of the gill as a valuable candidate for investigating PAH toxicity.

  7. Structural Characteristics and Immunological Activity of Glycosaminoglycan RG-1 from Ruditapes Philippinarum%菲律宾蛤仔糖胺聚糖RG-1的结构特征及免疫活性研究

    Institute of Scientific and Technical Information of China (English)

    范秀萍; 王瑞芳; 吴红棉; 王娅楠; 胡雪琼; 雷晓凌

    2012-01-01

    目的:对菲律宾蛤仔糖胺聚糖RG-1的一级结构特征及细胞免疫调节活性进行研究.方法:采用高效液相色谱法测定相对分子质量和单糖组成,通过红外光谱、高碘酸氧化和Smith降解等研究其糖链主要结构特征;用MTT法分析对小鼠脾淋巴细胞的影响.结果:RG-1主要由葡萄糖、氨基半乳糖和半乳糖通过1→6、1→4或1→4,6键连接构成主链,在主链中还含有大量的半乳糖醛酸,重均相对分子质量为9.94×105.RG-1具有显著增强小鼠腹腔巨噬细胞吞噬中性红的作用和脾淋巴细胞的增殖作用(p<0.01).结论:菲律宾蛤仔糖胺聚糖可通过增强细胞免疫活性而起到抗肿瘤作用.%Objective: To investigate the structural characterstics and cells immunomodulatory activity of the gly-Cosaminoglycan RG-1 from Ruditapes philippinarum. Methods: The morlicular weight and monosaccharide composition of the glycosaminoglycan RG-1 was analysed by HPGPC, its main structure characterstics was studied by IR, periodate oxidation and Smith degradation. Effects of RG-1 on proliferation of KM mouse spleen lymphocytes were detected by MTT. Results; RG-1 was composed of Glc-GalNAc-Gal by 1→6,1→4 or 1→4,6 in main chain backbone which contained much galacturonic acid with Mr 9.94×105. RG-1 significantly simulated the phagocytic activity of mice peritoneal macrophages and proliferation of KM mouse spleen lymphocytes in vitro (p<0.01). Conclusion:N Glycosaminoglycan RG-1 can inhibit the cancer by enhance cell immunological activity.

  8. Responses of Manila clam growth and its food sources to global warming in a subarctic lagoon in Japan

    Science.gov (United States)

    Yoon, Seokjin; Abe, Hiroya; Kishi, Michio J.

    2013-12-01

    Akkeshi Lake is a subarctic shallow brackish lagoon located in Hokkaido, Japan. The Manila clam, Ruditapes philippinarum, is cultured in sandy sediments at the shallow, intertidal flat near the mouth of the lake. To quantitatively evaluate the effects of environmental factors such as water temperature and food availability on the growth of the Manila clam and to estimate the responses of Manila clam growth and food availability to global warming in Akkeshi Lake, we developed a numerical model by coupling a three-dimensional ecosystem model with a bioenergetics model for the growth of the Manila clam. We ran the model under two different conditions: the present condition and the global warming condition. For the global warming condition, water temperature was increased by 2 °C at the open boundary for the entire computational period. The growth of the Manila clam was limited by water temperature and food availability. The Manila clam grew up to 1.33 g dry weight ind.-1 at the lake mouth (station A) for 5 years, whereas it grew up to 1.00 g dry weight ind.-1 at the lake center (station B). The difference in the biomass of the Manila clam between two stations was due to the difference in food availability. Under the global warming condition, the water temperature limitation for the Manila clam was relaxed with a water temperature increase. The Manila clam grew up to 1.55 g dry weight ind.-1 at station A and 1.10 g dry weight ind.-1 at station B. While the growth of the Manila clam was improved in the lake under the global warming condition, its food sources, especially phytoplankton, decreased because of ingestion increases of grazers.

  9. Manila clams from Hg polluted sediments of Marano and Grado lagoons (Italy) harbor detoxifying Hg resistant bacteria in soft tissues

    Energy Technology Data Exchange (ETDEWEB)

    Baldi, Franco, E-mail: baldi@unive.it [Dipartimento di Scienze Molecolari e Nanosistemi, Cà Foscari University of Venice, Dorsoduro 2137, 30123 Venice (Italy); Gallo, Michele; Marchetto, Davide [Dipartimento di Scienze Molecolari e Nanosistemi, Cà Foscari University of Venice, Dorsoduro 2137, 30123 Venice (Italy); Faleri, Claudia [Department of Environmental Science ‘G. Sarfatti’, University of Siena, 53100 Siena (Italy); Maida, Isabel; Fani, Renato [Dipartimento di Biologia Evoluzionistica, Via Romana, 17, University of Florence, 50125 Florence (Italy)

    2013-08-15

    A mechanism of mercury detoxification has been suggested by a previous study on Hg bioaccumulation in Manila clams (Ruditapes philippinarum) in the polluted Marano and Grado lagoons and in this study we demonstrate that this event could be partly related to the detoxifying activities of Hg-resistant bacteria (MRB) harbored in clam soft tissues. Therefore, natural clams were collected in six stations during two different periods (winter and spring) from Marano and Grado Lagoons. Siphons, gills and hepatopancreas from acclimatized clams were sterile dissected to isolate MRB. These anatomical parts were glass homogenized or used for whole, and they were lying on a solid medium containing 5 mg l{sup −1} HgCl{sub 2} and incubated at 30 °C. A total of fourteen bacterial strains were isolated and were identified by 16S rDNA sequencing and analysis, revealing that strains were representative of eight bacterial genera, four of which were Gram-positive (Enterococcus, Bacillus, Jeotgalicoccus and Staphylococcus) and other four were Gram-negative (Stenotrophomonas, Vibrio, Raoultella and Enterobacter). Plasmids and merA genes were found and their sequences determined. Fluorescence in situ hybridization (FISH) technique shows the presence of Firmicutes, Actinobacteria and Gammaproteobacteria by using different molecular probes in siphon and gills. Bacterial clumps inside clam flesh were observed and even a Gram-negative endosymbiont was disclosed by transmission electronic microscope inside clam cells. Bacteria harbored in cavities of soft tissue have mercury detoxifying activity. This feature was confirmed by the determination of mercuric reductase in glass-homogenized siphons and gills. -- Highlights: ► We isolated Gram-positive and Gram-negative Hg resistant strains from soft tissues of Ruditapes philippinarum. ► We identify 14 mercury resistant strains by 16S rRNA gene sequences. ► Bacteria in siphon and gill tissues of clams were observed by TEM and identified

  10. Effect of TBT on Ruditapes decussatus juveniles.

    Science.gov (United States)

    Coelho, M R; Langston, W J; Bebianno, M J

    2006-06-01

    The effects of sublethal concentrations of tributyltin (TBT) on growth of juvenile clams Ruditapes decussatus were determined during exposure to TBT concentrations of 50, 100 and 250 ng l(-1) (as Sn) for a period up to two years. Length and weight of clams increased continuously in all treatments throughout the experimental period, and, overall, rates were not significantly influenced by TBT exposure, although final length and weight were inversely related to increasing TBT concentration. Juvenile R. decussatus therefore appear to be less sensitive to TBT than larval stages. Some juveniles exposed to TBT developed abnormal shell growth, laterally, changing the typical flattened shape of clams into a more "rounded" form. This characteristic was more visible in the anterior margins of valves than posteriorly, and mainly observed in clams exposed to TBT at 50 ng l(-1) (as Sn).

  11. Evaluation of toxicological effects induced by tributyltin in clam Ruditapes decussatus using high-resolution magic angle spinning nuclear magnetic resonance spectroscopy: Study of metabolic responses in heart tissue and detection of a novel metabolite

    Directory of Open Access Journals (Sweden)

    H. Hanana

    2014-01-01

    The main finding of this study was the appearance of an original metabolite after TBT treatment likely N-glycine-N′-alanine. It is the first time that this molecule has been identified as a natural compound. Its exact role is unknown and remains to be elucidated. We suppose that its formation could play an important role in clam defense response by attenuating Ca2+ dependent cell death induced by TBT. Therefore this compound could be a promising biomarker for TBT exposure.

  12. Oxidative stress biomarkers and bioconcentration of reldan and roundup by the edible clam Ruditapes decussatus%可食用文蛤中氧化性胁迫的生物标记物与甲基毒死蜱和草甘膦的生物富集

    Institute of Scientific and Technical Information of China (English)

    Ismail M. ABDEL-NABI; Nahla S. EL-SHENAWY; Inas A. TAHA; Tarak S. MOAWAD

    2007-01-01

    近几十年期间,在种群和个体受干扰后,对作为早期指示剂的生物标记物的研究受到越来越多的关注.我们用对水生生态系统污染敏感的生物标记物双壳类软体动物(文蛤)来评估两种有机磷杀虫剂(甲基毒死蜱、草甘膦)的影响.文蛤是水生生态系统污染的一种敏感的指示物种.在不同时间段测定文蛤中不同组织的非酶的(谷胱苷肽)和酶的(过氧化氢酶)抗氧化剂,作为文蛤中生物标记物的反应.在实验室条件下,测定了脂质过氧化作用、蛋白羰基含量、总蛋白含量、总脂质含量以及胆碱酯酶的活性.对不同的生物标记与杀虫剂的生物体内积累的相互关系进行了研究.甲基毒死蜱在文蛤组织中具有最大的诱导氧化胁迫的潜能,导致脂质过氧化反应增加并抑制抗氧化剂.而且,鳃是对该反应最敏感的器官.文蛤是一种极好的甲基毒死蜱的积聚者,因为暴露60天后,可以测定到其组织中浓度为824.0 mg/kg w.w的甲基毒死蜱.随着在草甘膦中暴露时间的增加,与背景水平相比,组织中草甘膦的浓度增加大约8×103 mg/kg w.w.可以得出这样的结论:在一种生物中测定几种生物标记物是有用的.在双壳类中,蛋白质的羰基诱导可用于双壳类中化学污染物诱导的氧化胁迫的生物指示剂.抗氧化剂的防御成分是敏感的参数,是评估污染的水生生态系统的有用的生物标记物.辅以蛤组织的化学分析,生物标记参数能够提供一种有力的监测工具.%Research on biomarkers as early indicators of perturbation in populations and individuals has received increasing interest during recent decades. We used bivalve molluscs (clams), which are known to be biomarkers sensitive to aquatic ecosystem pollution, in order to assess the effects of two organophosphorus pesticides:reldan and roundup. Biomarker responses of Ruditapes decussatus were assessed by measuring non

  13. Heavy metals in oysters, mussels and clams collected from coastal sites along the Pearl River Delta, South China

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Concentrations of 8 heavy metals: cadmium (Cd), copper(Cu), zinc (Zn), lead (Pb), nickel (Ni), chromium (Cr), antimony(Sb) and tin (Sn) were examined in 3 species of bivalves (Pernaviridis, Crassostrea rivularis and Ruditapes philippinarum)collected from 25 sites along the Pearl River Delta coastal watersin the South China Sea from July to August 1996. In general, Cd,Cu, Zn and Sn concentrations in the three bivalve species collectedfrom the Estuarine Zone were significantly higher than thosecollected from the Western and Eastern Zones of the Pearl RiverDelta, which are related to the existence of various anthropogenicactivities in the catchment of the Pearl River Delta. The WesternEstuarine Zone is mainly impacted by Cr, Ni and Cu contamination.In Victoria Harbor, heavy metal contamination is mainly due to Cuand Pb. Cd, Cu and Zn concentrations in oysters were significantlyhigher than those in mussels and clams. This could be explained bythe fact that oysters live mainly in the Estuarine Zone of thePearl River Delta which receives most of the polluting dischargesfrom the catchment of the Delta. During turbid condition, heavymetals (soluble or adsorbed on suspended particulates) dischargedfrom the Delta are filtered from the water column and subsequentlyaccumulated into the soft body tissues of oysters. Heavy metalconcentrations in the three bivalve species were compared with themaximum permissible levels of heavy metals in seafood regulated bythe Public Health and Municipal Services Ordinance, Laws of HongKong, and it was revealed that Cd and Cr concentrations in thethree bivalve species exceeded the upper limits. At certainhotspots in the Delta, the maximum acceptable daily load for Cd wasalso exceeded.

  14. Habitat Preferences and Growth of Ruditapes bruguieri (Bivalvia: Veneridae at the Northern Boundary of Its Range

    Directory of Open Access Journals (Sweden)

    Alla V. Silina

    2014-01-01

    Full Text Available This work is the first attempt to study growth and some morphological parameters of the clam Ruditapes bruguieri, as well as its habitat preferences. It is found that R. bruguieri lives on bottom sediments including pebble and coarse- and medium-grained sand with a slight admixture of silt. At the study area, this bivalve inhabits sea waters with good aeration, stable oceanic water salinity, and a high oxygen concentration. The annual fluctuations of the water temperature from 13-14°C (in winter to 22–29°C (in summer are close to the threshold temperature values, within which the species can exist. Near the boundary of the species range, along the Jeju Island coasts, south of Republic of Korea, 83.8% of all clams die during the coldest period of the year. Here, annual rings are formed on R. bruguieri shells during winter. The maximum age of R. bruguieri, determined during the study, is 6.5 years, but the clam samples contain mainly individuals at 3.0–3.5 years of age (34%. The largest clam dimensions are 36.0 × 26.5 mm (length × height of shell. At the study area, a usual shell length is 20.0–32.0 mm (75% of all the collected individuals.

  15. 温度对菲律宾蛤仔滤食率、清滤率和吸收率的影响%THE EFFECT OF TEMPERATURE ON THE FILTRATION RATE, CLEARANCE RATE AND ABSORPTION EFFICIENCY OF MANILA CLAM, RUDITAPES PHILIPPINARUM

    Institute of Scientific and Technical Information of China (English)

    董波; 薛钦昭; 李军

    2000-01-01

    于1997年12月,1998年3月、7月,1999年8月在中国科学院海洋研究所实验室采用静水方法对9土0.1℃,16土0.5℃,22土0.2℃,26±0.6℃下菲律宾蛤仔的滤食率FR、清滤率CR、吸收率AE进行了测定.结果表明,在9~22℃温度范围内蛤仔滤食率、清滤率、吸收率均随温度的升高而增大,在22℃达到最大值,并且各温度间差异显著(ANOVA,P<0.05).当温度达到26℃时,滤食率、清滤率、吸收率均有所下降,但和22℃值比较差异并不显著(ANOVA,P>0.2).说明蛤仔对温度有很强的适应能力,其生长最适温度为22℃左右.

  16. Cloning and characterization of cDNA probes for the analysis of metallothionein gene expression in the Mediterranean bivalves: Ruditapes decussatus and Cerastoderma glaucum.

    Science.gov (United States)

    Ladhar-Chaabouni, Rim; Mokdad-Gargouri, Raja; Denis, Françoise; Hamza-Chaffai, Amel

    2009-05-01

    cDNA probes have been developed for subsequent use in monitoring the cadmium exposure of the clam Ruditapes decussatus and the cockle Cerastoderma glaucum using metallothionein (MT) gene expression in different tissues of these species. Two partial MT cDNAs were isolated from Ruditapes decussatus and Cerastoderma glaucum. The identification of the nucleotide sequences showed that the cDNAs consist of 480 bp coding 72 amino acid proteins containing 21 cysteine residues organized in Cys-X-Cys motifs as classically described for MTs. The induction of MT gene expression in CdCl(2) treated bivalves was confirmed by dot blot analysis and suggests a potential specific tissue expression rate.

  17. Physiological and biochemical responses of three Veneridae clams exposed to salinity changes.

    Science.gov (United States)

    Carregosa, Vanessa; Velez, Cátia; Soares, Amadeu M V M; Figueira, Etelvina; Freitas, Rosa

    2014-01-01

    Given their global importance, coastal marine environments are a major focus of concern regarding the potential impacts of climate change, namely due to alterations in seawater salinity. It is known that environmental characteristics, such as salinity, affect immune and physiological parameters of bivalves. Nevertheless, scarce information is available concerning the biochemical alterations associated with salinity changes. For this reason, the present work aimed to evaluate the biochemical responses of three venerid clam species (Venerupis decussata, Venerupis corrugata, Venerupis philippinarum) submitted to salinity changes. The effects on the native (V. decussata and V. corrugata) and invasive (V. philippinarum) species collected from the same sampling site and submitted to the same salinity gradient (0 to 42g/L) were compared. The results obtained demonstrated that V. corrugata is the most sensitive species to salinity changes and V. decussata is the species that can tolerate a wider range of salinities. Furthermore, our work showed that clams under salinity associated stress can alter their biochemical mechanisms, such as increasing their antioxidant defenses, to cope with the higher oxidative stress resulting from hypo and hypersaline conditions. Among the physiological and biochemical parameters analyzed (glycogen and protein content; lipid peroxidation levels, antioxidant enzymes activity; total, reduced and oxidized glutathione) Catalase (CAT) and especially superoxide dismutase (SOD) showed to be useful biomarkers to assess salinity impacts in clams.

  18. Strict sex-specific mtDNA segregation in the germ line of the DUI species Venerupis philippinarum (Bivalvia: Veneridae).

    Science.gov (United States)

    Ghiselli, Fabrizio; Milani, Liliana; Passamonti, Marco

    2011-02-01

    Doubly Uniparental Inheritance (DUI) is one of the most striking exceptions to the common rule of standard maternal inheritance of metazoan mitochondria. In DUI, two mitochondrial genomes are present, showing different transmission routes, one through eggs (F-type) and the other through sperm (M-type). In this paper, we report results from a multiplex real-time quantitative polymerase chain reaction analysis on the Manila clam Venerupis philippinarum (formerly Tapes philippinarum). We quantified M- and F-types in somatic tissues, gonads, and gametes. Nuclear and external reference sequences were used, and the whole experimental process was designed to avoid any possible cross-contamination. In most male somatic tissues, the M-type is largely predominant: This suggests that the processes separating sex-linked mitochondrial DNAs (mtDNAs) in somatic tissues are less precise than in other DUI species. In the germ line, we evidenced a strict sex-specific mtDNA segregation because both sperm and eggs do carry exclusively M- and F-types, respectively, an observation that is in contrast with a previous analysis on Mytilus galloprovincialis. More precisely, whereas two mtDNAs are present in the whole gonad, only the sex-specific one is detected in gametes. Because of this, we propose that the mtDNA transmission is achieved through a three-checkpoint process in V. philippinarum. The cytological mechanisms of male mitochondria segregation in males and degradation in females during the embryo development (here named Checkpoint #1 and Checkpoint #2) are already well known for DUI species; a Checkpoint #3 would act when primordial germ cells (PGCs) are first formed and would work in both males and females. We believe that Checkpoint #3 is a mere variation of the "mitochondrial bottleneck" in species with standard maternal inheritance, established when their PGCs separate during embryo cleavage.

  19. An Experimental Study on Optimization for Polyculture of Portunus trituberculatus with Litopenaeus vannamei, Ruditapes philip pinarum and Gracilaria lichevoides%三疣梭子蟹、凡纳滨对虾、菲律宾蛤仔和江蓠混养结构优化的实验研究

    Institute of Scientific and Technical Information of China (English)

    班文波; 田相利; 董双林; 张凯; 高明亮; 张东旭; 奉杰; 张庆起

    2015-01-01

    The study was designed and conducted to optimize the structure of polyculture for Portunus trituberculatus ,Litopenaeus vannamei ,Ruditapes philippinarum and Gracilaria lichevoides ,and to compare their water quality parameters .Crabs ,shrimps and clams were mixed with Gracilaria lichev‐oides ,six treatments were designed respectively was C ,CS ,CSB ,CSBJ1 ,CSBJ2 ,CSBJ3 (C :crab ;S :shrimp;B :clam ;J :Gracilaria lichevoides) .The result showed that the individual specifications of crabs in different treatments were not significantly different(P>0 .05);The highest yield of crab were 3255 .24 kg/hm2 for the treatment of CSBJ2 ;The body weight ,sgr and survival rate of CSBJ1 and CS‐BJ2 were significantly higher than other treatments(P0 .05);During the period of culturing ,there were significantly lower NO2 -N in CSBJ2 than in other treatments on the whole(P<0 .05);The treatments which mixed with Gracilaria lichevoides could significantly reduce the concentration of ammonia nitrogen(P< 0 .05) . Total nitrogen and total phosphorus concentration of CSBJ1 and CSBJ2 were significantly lower than other treatments in the middle and late cultivation(P<0 .05) .In this study , Portunus trituberculatus system mixed with Gracilaria lichevoides in suitable density could improve water quality ,reduce the concentration of total nitrogen ,total phosphorus and ammonia nitrogen ,nitrate nitrogen and improve the production and survival rate of Portunus trituberculatus and Litopenaeus vannamei .Under the condition of this research ,the treatment giving the best culturing benefit was crabs at 6 ind/m2 , shrimps at 45 ind/m2 and clams at 45 ind/m2 ,Gracilaria lichevoides at 0 .36 kg/m2 .%利用海水陆基实验围隔优化了三疣梭子蟹(Portunus trituberculatus)、凡纳滨对虾(Litopenaeus van‐namei)、菲律宾蛤仔(Ruditapes philippinarum)和菊花江蓠(Gracilaria lichevoides)的混养结构。实验设6个处理组,分别为蟹-虾(CS)、蟹-虾

  20. The effects of clam fishing on the properties of surface sediments in the lagoon of Venice, Italy

    Directory of Open Access Journals (Sweden)

    R. J. Aspen

    2004-01-01

    Full Text Available Harvesting of clams(Tapes philippinarum has important socio-economic and environmental implications for the Venice lagoon area, Italy. Clam harvesting disrupts the structure of benthic communities but the effects upon sediment stability and surface structure remain unclear. The effect of clam fishing on the sediment properties of the lagoon bed was investigated at two different sites, a heavily fished site (San Angelo and an infrequently fished site (San Giaccomo. Both sites were assessed for immediate impacts of fishing, using indicators of biogenic sediment stabilisation. Samples were taken at three points along three 100 m linear transects at each site prior to and post fishing. Paired samples were also taken parallel to each transect at a distance of 5m, to allow for temporal variation. Sediment stability, measured with a cohesive strength meter (CSM, was significantly higher at the less impacted site (F1,34 = 6.23, p a (chl a, colloidal-S carbohydrate and dry bulk density were observed on the transect after fishing but not adjacent to the fishing path. At the heavily impacted site, clam fishing by trawling had, in general, no significant effect on the biological and physical properties (although chl a did decrease significantly after fishing. The lack of a significant impact from fishing at the impacted site was attributed to the higher frequency of fishing occurring in this area. Hence, frequent fishing of the lagoon prevents establishment of biotic communities, preventing biostabilisation and thus reduces the stability of the surface sediment. Keywords: clam harvesting, erosion threshold, microphytobenthos, sediment, stability

  1. The Functional Diversity of Flora in Polyculture Ecosystem of Swimming Crab, Shrimp and Short-necked Clam%蟹虾贝混养池塘生态系统微生物群落功能多样性研究

    Institute of Scientific and Technical Information of China (English)

    刘瑞娟; 田相利; 董双林; 张凯; 阳钢; 闫法军

    2014-01-01

    The functional diversity of flora was studied in four polyculture ecosystems including swimming crab Portunus trituberculatus ,Chinese shrimp Fenneropenaeus chinensis and short-necked clam Ruditapes philippinarum (B) ,swimming crab ,Pacific whiteleg shrimp Litopenaeus vannamei ,and short-necked clam (C) ,swimming crab ,kuruma shrimp Marsupeaaeus japonicus ,and short- necked clam (D) ,and monoculture of swimming crab (A ,as control group) using ECO-BIOLOG kit .The results showed that there were different metabolisms of the flora and utilization strength of substrate carbon in various ecosys-tems during the culture period .(1) The flora had gradual increase in metabolic activity in Chinese shrimp , short-necked clam and swimming crab polyculture ecosystem as time elapsed .In the later experiment , there was significantly higher metabolic activity of the flora in B and C polyculture modes than that in A mode (monoculture mode) .(2) In the later experiment ,there was significantly higher utilization of sub-strate carbon in B and D polyculture modes than that in A mode (P<0 .05) .(3) In the later experiment , significant differences in Shannon index and Simpson index were observed in the flora in the different eco-systems (P<0 .05) .The McIntosh index ,however ,was significant difference during the entire experi-ment (P<0 .05) .The three diversity indices of the flora were significantly higher in the Chinese shrimp and white shrimp polyculture modes than that in the monoculture of swimming crab (P<0 .05) .The find-ings indicate that the ecosystem structure and function of the flora can be further improved by the polycul-ture swimming crab ,and short-necked clam with Pacific whiteleg shrimp .%应用BIOLOG生态微板研究了三疣梭子蟹不同混养生态系统的细菌群落功能多样性,包括三疣梭子蟹和菲律宾蛤仔分别与中国明对虾、凡纳滨对虾和日本囊对虾混养系统,以三疣梭子蟹单养作为对照。结果表明,不同养

  2. Isolation and characterization of an antibacterium against Vibrio harveyi 11593 from a mixed pond with penaeus japonicus bate, portunus trituberculatus and ruditapes philippinarum in China

    Science.gov (United States)

    An, X. H.; Xu, Y. J.; Li, F. H.; Ma, G. Z.; Li, L. T.

    2016-08-01

    Aquaculture diseases, particularly Vibriosis, are becoming a pressing concern due to incurred aquacultural loss in China. Commercial antibiotics may be used to control it, but its increased antibiotic resistance to prominent pathogenic bacteria has become a prevalent problem nationwide, and a global threat to public health. Probiotics are recommended instead because they are healthy, environment-friendly, and capable of maintaining productivity. An antibacterium against Vibrio harveyi 11593 was isolated from a mariculture pond with shrimp, crabs, and shellfish in China. The bacterium, E14, has an inhibitory zone diameter (DIZ) of 24.5 ± 0.5 mm. The strain was identified as Bacillus pumilus based on morphological observation, conventional biochemical tests, and 16S rDNA sequence analysis. The gram-positiveand motile bacterium is around 1.10-1.32 pm × 0.67-0.83 μm in size. Optimized conditions for antimicrobial substance production of B. pumilus E14 require that it be cultured for 26 h at 28 °C, with an initial pH of 7.0 in 100 mL/500 mL LB with 3% NaCl. The B. pumilus E14 cultures were confirmed to be safe and efficacious and actually worked to protect the host animal in shrimp larvae (Penaeus chinensis) culture. The B. pumilus E14 obtained in this study strengthened the strain's defense against aquaculture disease and made a good candidate for an alternative probiotics and benefit to sustainability of aquaculture.

  3. 33 CFR 117.323 - Outer Clam Bay

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Outer Clam Bay 117.323 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.323 Outer Clam Bay The drawspan of the Outer Clam Bay Boardwalk Drawbridge shall open on signal if at least 30 minutes advance notice is given....

  4. ClamWin Free Antivirus

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    ClamWin是在自由软件基金会(Free Software Foundation)支持下的一个杀毒软件开发项目。因此软件使用与传播均是免费的(当然传播要遵从GNL协议了)。杀毒软件的目前版本是0.88,实际上还处于较为初级的阶段,但查杀病毒这一主体功能是值得信赖的。软件没有采用添加到系统服务的自启动方式,这样做的一个好处是系统资源占用率极低,在监视状态下仅开启一个两、三兆大小的进程。软件杀毒时速度较慢,并且没有“加速”选项可设置。

  5. Analysis of Hongdao Clam Industrial Structure Based on Industry Chain

    Institute of Scientific and Technical Information of China (English)

    Jiang; Xianqiong

    2014-01-01

    The vertical and transverse structures of Hongdao clam industry are described and analyzed objectively based on the perspective of industry chain. On the basis of field investigation,the key nodes of Hongdao clam industry chain,including nursery,breeding,processing,transportation and sale,are analyzed. It can be concluded that the development of clam industry chain is unbalanced,especially the deep-processing capacity is not strong,and the development of supporting industy lags behind. The horizontal industry chain of clam needs to be further improved. The corresponding suggestions are put forward: strengthening research on new nursery technology in later period,further extending the horizontal industry chain of clam,mining the depth of clam-related leisure industry,and upgrading service level of leisure travel.

  6. Taxonomy of Indonesian giant clams (Cardiidae, Tridacninae)

    OpenAIRE

    UDHI EKO HERNAWAN

    2012-01-01

    Hernawan E. 2012. Taxonomy of Indonesian giant clams (Cardiidae, Tridacninae). Biodiversitas 13: 118-123. A taxonomic study was conducted on the giant clam’s specimens deposited in Museum Zoologicum Bogoriense (MZB), Cibinong Indonesia. Taxonomic overviews of the examined specimens are given with diagnostic characters, remarks, habitat and distribution. Discussion is focused on specific characters distinguishing each species. From seven species known to distribute in Indonesian waters, there ...

  7. Host-parasite interactions: Marine bivalve molluscs and protozoan parasites, Perkinsus species.

    Science.gov (United States)

    Soudant, Philippe; E Chu, Fu-Lin; Volety, Aswani

    2013-10-01

    This review assesses and examines the work conducted to date concerning host and parasite interactions between marine bivalve molluscs and protozoan parasites, belonging to Perkinsus species. The review focuses on two well-studied host-parasite interaction models: the two clam species, Ruditapes philippinarum and R. decussatus, and the parasite Perkinsus olseni, and the eastern oyster, Crassostrea virginica, and the parasite Perkinsus marinus. Cellular and humoral defense responses of the host in combating parasitic infection, the mechanisms (e.g., antioxidant enzymes, extracellular products) employed by the parasite in evading host defenses as well as the role of environmental factors in modulating the host-parasite interactions are described.

  8. Spatial partitioning between species of the phytoplankton-feeding guild on an estuarine intertidal sand flat and its implication on habitat carrying capacity

    Science.gov (United States)

    Tamaki, Akio; Nakaoka, Ayumi; Maekawa, Hideki; Yamada, Fumihiko

    2008-07-01

    The fishery yield of Manila clams, Ruditapes philippinarum, increased considerably in the 1970s but has decreased rapidly since the middle 1980s on extensive intertidal sand flats in Ariake Sound (Kyushu, Japan). A survey conducted in 2004 on a 3.4-km 2 sand flat located in the central part of the Sound (Shirakawa sand flat) revealed four dominant species: two thalassinidean shrimps ( Upogebia major and Nihonotrypaea japonica), which are deep-reaching burrow dwellers with strong bioturbation activities, and two bivalves ( Mactra veneriformis and R. philippinarum). All four species belong to a phytoplankton (diatom)-feeding guild. In the late 1970s, the Manila clam population prevailed in high densities over the entire sand flat, whereas its distribution was restricted to the lowest quarter of the shore in 2004. In contrast, the population sizes and zones of occurrence of the other phytoplankton feeders have expanded in the absence of R. philippinarum, perhaps an indication of competitive release. After establishment, effects of the thalassinidean shrimps on sediment stability appear to have further reduced clam abundances. Across the sand flat in 2004, wet weight population biomass estimates for N. japonica, U. major, M. veneriformis, and R. philippinarum (whole body for shrimps and soft tissue for bivalves) were 304, 111, 378, and 234 tonnes, respectively. Based on Manila clam fishery yield records from Shirakawa, the carrying capacity of the Shirakawa sand flat in the late 1970s was estimated to be two times greater than the sum value for the whole phytoplankton-feeding guild in 2004. It is hypothesized that (1) the amount of phytoplankton determines the carrying capacity for the benthic community on the Shirakawa sand flat, with both phytoplankton and benthic biomass at maxima in the late 1970s, and (2) the subsequent increases in competition for space have caused further declines in the Manila clam population biomass to approximately one-eighth of its past

  9. Autochthonous clams monitoring of Ganzirri Lake (Sicily).

    Science.gov (United States)

    Di Bella, Giuseppa; Cavallaro, Novella; Lo Turco, Vincenzo; Furci, Patrizia; Rando, Rossana; La Pera, Lara; Dugo, Giacomo

    2010-12-01

    Two autochthonous clams, Venerupis aurea laeta and Cerastoderma edule/glaucum, collected for a period of 1 year, from May 2007 to January 2008, were studied in the Cape Peloro lagoon. On the samples, it was evaluated the presence of pathogenic microorganisms and proteins, lipids and yield edible part were determined. It was evaluated the concentration of mineral elements (Cd, Cu, Mn, Se, Pb, Zn) and organic contaminants (∑DDT and PCBs). Salmonella is never present in any sample. Total and faecal coliform values have always been under law limits for alive bivalves mussels production and sale. Zn, Cu, Cd and Pb levels were found in clams where they are slightly lower too. Both species do not show significant changes for Mn and Se. DDT and PCBs traces were discovered in Ganzirri Lake' samples, but in all observed cases, they were below law limits. As a result of all these observations, it is clear that, in recent years, the bivalve's use of Ganzirri Lake does not denote toxicological risk to human health.

  10. Application of electron-beam irradiation on the production of salted and seasoned short-necked clam, Tapes Pilippinarum, for safe distribution

    Science.gov (United States)

    Kim, B.; Song, H. P.; Choe, J. H.; Jung, S.; Jang, A.; Kim, Y. J.; Jo, C.

    2009-07-01

    Salted and seasoned short-necked clam ( Tapes Philippinarum; SNC) and its major ingredients, red hot pepper powder, ginger, garlic and onion were irradiated at 0.5, 1, 2 and 5 kGy, respectively, and the microbiological and sensory quality were evaluated. The water activities of SNC and red pepper powder were 0.91 and 0.56, respectively, and others were higher than 0.97. The initial microbial populations of SNC were approximately 3.99, 4.38 and 2.22 log CFU/g for total aerobic bacteria, yeast and mold, and coliform bacteria. The highest contamination of total aerobic bacteria was detected from ground ginger among ingredients at 5.51 log CFU/g. Electron-beam irradiation (0, 0.5, 1, 2 and 5 kGy) significantly reduced the initial microbial level of SNC and its ingredients not only immediately after irradiation, but also during storage at 10 °C for 4 weeks ( pcontrol. From the results electron-beam irradiation is a useful tool to enhance the storage stability and safe distribution of SNC.

  11. Application of electron-beam irradiation on the production of salted and seasoned short-necked clam, Tapes Pilippinarum, for safe distribution

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B.; Song, H.P.; Choe, J.H.; Jung, S. [Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Jang, A. [Quality Control and Utilization of Animal Products, National Institute of Animal Science, Suwon 441-706 (Korea, Republic of); Kim, Y.J. [Food Safety Research Division, Korea Food Research Institute, Seongnam 463-746 (Korea, Republic of); Jo, C. [Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 305-764 (Korea, Republic of)], E-mail: cheorun@cnu.ac.kr

    2009-07-15

    Salted and seasoned short-necked clam (Tapes Philippinarum; SNC) and its major ingredients, red hot pepper powder, ginger, garlic and onion were irradiated at 0.5, 1, 2 and 5 kGy, respectively, and the microbiological and sensory quality were evaluated. The water activities of SNC and red pepper powder were 0.91 and 0.56, respectively, and others were higher than 0.97. The initial microbial populations of SNC were approximately 3.99, 4.38 and 2.22 log CFU/g for total aerobic bacteria, yeast and mold, and coliform bacteria. The highest contamination of total aerobic bacteria was detected from ground ginger among ingredients at 5.51 log CFU/g. Electron-beam irradiation (0, 0.5, 1, 2 and 5 kGy) significantly reduced the initial microbial level of SNC and its ingredients not only immediately after irradiation, but also during storage at 10 {sup o}C for 4 weeks (p<0.05). There was no adverse change of sensory score except for the color of onion irradiated at 5 kGy, which results in a lower score than control. From the results electron-beam irradiation is a useful tool to enhance the storage stability and safe distribution of SNC.

  12. Razor clam to RoboClam: burrowing drag reduction mechanisms and their robotic adaptation.

    Science.gov (United States)

    Winter, A G; V; Deits, R L H; Dorsch, D S; Slocum, A H; Hosoi, A E

    2014-09-01

    Estimates based on the strength, size, and shape of the Atlantic razor clam (Ensis directus) indicate that the animal's burrow depth should be physically limited to a few centimeters; yet razor clams can dig as deep as 70 cm. By measuring soil deformations around burrowing E. directus, we have found the animal reduces drag by contracting its valves to initially fail, and then fluidize, the surrounding substrate. The characteristic contraction time to achieve fluidization can be calculated directly from soil properties. The geometry of the fluidized zone is dictated by two commonly-measured geotechnical parameters: coefficient of lateral earth pressure and friction angle. Calculations using full ranges for both parameters indicate that the fluidized zone is a local effect, occurring between 1-5 body radii away from the animal. The energy associated with motion through fluidized substrate-characterized by a depth-independent density and viscosity-scales linearly with depth. In contrast, moving through static soil requires energy that scales with depth squared. For E. directus, this translates to a 10X reduction in the energy required to reach observed burrow depths. For engineers, localized fluidization offers a mechanically simple and purely kinematic method to dramatically reduce energy costs associated with digging. This concept is demonstrated with RoboClam, an E. directus-inspired robot. Using a genetic algorithm to find optimal digging kinematics, RoboClam has achieved localized fluidization burrowing performance comparable to that of the animal, with a linear energy-depth relationship, in both idealized granular glass beads and E. directus' native cohesive mudflat habitat.

  13. Taxonomy of Indonesian giant clams (Cardiidae, Tridacninae

    Directory of Open Access Journals (Sweden)

    UDHI EKO HERNAWAN

    2012-07-01

    Full Text Available Hernawan E. 2012. Taxonomy of Indonesian giant clams (Cardiidae, Tridacninae. Biodiversitas 13: 118-123. A taxonomic study was conducted on the giant clam’s specimens deposited in Museum Zoologicum Bogoriense (MZB, Cibinong Indonesia. Taxonomic overviews of the examined specimens are given with diagnostic characters, remarks, habitat and distribution. Discussion is focused on specific characters distinguishing each species. From seven species known to distribute in Indonesian waters, there are six species, Tridacna squamosa Lamarck, 1819; T. gigas Linnaeus, 1758; T. derasa Roding, 1798; T. crocea Lamarck, 1819; T. maxima Roding,1798; and Hippopus hippopus Linnaeus, 1758. This study suggests the need for collecting specimen of H. porcellanus Rosewater, 1982. Important characters to distinguish species among Tridacninae are interlocking teeth on byssal orifice, life habits, presence of scales and inhalant siphon tentacles.

  14. Interim Breeding of Manila Clam Ruditapes philippenarum in Earthen Ponds%菲律宾蛤仔土池中间育成的研究

    Institute of Scientific and Technical Information of China (English)

    闫喜武; 张国范; 杨凤; 孙茂盛

    2006-01-01

    2002~2003年在约80 hm2土池进行了菲律宾蛤仔中间育成试验.试验结果表明,在适时肥水、追肥、清池,水温20~25 ℃的条件下,放养密度3.0×104~5.0×104枚/m2,放养规格>1.5 mm,平均生长速度>80 μm/d,最高可达250 μm/d,成活率>80%;不适时肥水、追肥、清池,放养规格又偏小(壳长<0.4 mm)条件下,平均生长速度为26.6μm/d,成活率只有30%.表明放养规格、肥水、追肥、清池及适时疏苗是影响中间育成效果的主要因素.

  15. Molluscs and echinoderms aquaculture: biological aspects, current status, technical progress and future perspectives for the most promising species in Italy

    Directory of Open Access Journals (Sweden)

    Antonio Pais

    2012-10-01

    Full Text Available Shellfish aquaculture is a widespread activity in the Italian peninsula. However, only two bivalve species are mainly cultured along the coastline of that country: the Mediterranean mussel Mytilus galloprovincialis and the Manila clam Venerupis philippinarum (Ruditapes philippinarum. By contrast, just a few other mollusc species of commercial interest are scarcely reared at a small-scale level. After analysing the current status of Italian shellfish production, this paper reports and discusses the potential for culturing several different invertebrate species [i.e., the European flat oyster Ostrea edulis, the grooved carpet shell Venerupis decussata (Ruditapes decussatus, the razor clams Ensis minor and Solen marginatus, the cephalopod Octopus vulgaris, and the purple sea urchin Paracentrotus lividus] in this country. In addition, a detailed overview of the progress made in aquacultural techniques for these species in the Mediterranean basin is presented, highlighting the most relevant bottlenecks and the way forward to shift from the experimental to the aquaculture phase. Finally, an outlook of the main economic and environmental benefits arising from these shellfish culture practices is also given.

  16. Ancient clam gardens increased shellfish production: adaptive strategies from the past can inform food security today.

    Science.gov (United States)

    Groesbeck, Amy S; Rowell, Kirsten; Lepofsky, Dana; Salomon, Anne K

    2014-01-01

    Maintaining food production while sustaining productive ecosystems is among the central challenges of our time, yet, it has been for millennia. Ancient clam gardens, intertidal rock-walled terraces constructed by humans during the late Holocene, are thought to have improved the growing conditions for clams. We tested this hypothesis by comparing the beach slope, intertidal height, and biomass and density of bivalves at replicate clam garden and non-walled clam beaches in British Columbia, Canada. We also quantified the variation in growth and survival rates of littleneck clams (Leukoma staminea) we experimentally transplanted across these two beach types. We found that clam gardens had significantly shallower slopes than non-walled beaches and greater densities of L. staminea and Saxidomus giganteus, particularly at smaller size classes. Overall, clam gardens contained 4 times as many butter clams and over twice as many littleneck clams relative to non-walled beaches. As predicted, this relationship varied as a function of intertidal height, whereby clam density and biomass tended to be greater in clam gardens compared to non-walled beaches at relatively higher intertidal heights. Transplanted juvenile L. staminea grew 1.7 times faster and smaller size classes were more likely to survive in clam gardens than non-walled beaches, specifically at the top and bottom of beaches. Consequently, we provide strong evidence that ancient clam gardens likely increased clam productivity by altering the slope of soft-sediment beaches, expanding optimal intertidal clam habitat, thereby enhancing growing conditions for clams. These results reveal how ancient shellfish aquaculture practices may have supported food security strategies in the past and provide insight into tools for the conservation, management, and governance of intertidal seascapes today.

  17. Ancient clam gardens increased shellfish production: adaptive strategies from the past can inform food security today.

    Directory of Open Access Journals (Sweden)

    Amy S Groesbeck

    Full Text Available Maintaining food production while sustaining productive ecosystems is among the central challenges of our time, yet, it has been for millennia. Ancient clam gardens, intertidal rock-walled terraces constructed by humans during the late Holocene, are thought to have improved the growing conditions for clams. We tested this hypothesis by comparing the beach slope, intertidal height, and biomass and density of bivalves at replicate clam garden and non-walled clam beaches in British Columbia, Canada. We also quantified the variation in growth and survival rates of littleneck clams (Leukoma staminea we experimentally transplanted across these two beach types. We found that clam gardens had significantly shallower slopes than non-walled beaches and greater densities of L. staminea and Saxidomus giganteus, particularly at smaller size classes. Overall, clam gardens contained 4 times as many butter clams and over twice as many littleneck clams relative to non-walled beaches. As predicted, this relationship varied as a function of intertidal height, whereby clam density and biomass tended to be greater in clam gardens compared to non-walled beaches at relatively higher intertidal heights. Transplanted juvenile L. staminea grew 1.7 times faster and smaller size classes were more likely to survive in clam gardens than non-walled beaches, specifically at the top and bottom of beaches. Consequently, we provide strong evidence that ancient clam gardens likely increased clam productivity by altering the slope of soft-sediment beaches, expanding optimal intertidal clam habitat, thereby enhancing growing conditions for clams. These results reveal how ancient shellfish aquaculture practices may have supported food security strategies in the past and provide insight into tools for the conservation, management, and governance of intertidal seascapes today.

  18. Toxicity of a traditional molluscicide to asian clam veligers

    Science.gov (United States)

    Layhee, Megan J.; ,; Miho Yoshioka,; Bahram Farokhkish,; ,; Gross, Jackson A.; Sepulveda, Adam J.

    2014-01-01

    Aquaculture and hatchery industries are in need of effective control methods to reduce the risk of spreading aquatic invasive species, such as the Asian clam Corbicula fluminea, through aquaculture and hatchery activities. The planktonic nature of Asian clam veligers enables this life stage to enter water-based infrastructure undetected, including hatchery trucks used to stock fish. Once in hatchery trucks, veligers can disperse overland and establish in previously uninvaded habitats. As a result, there is a need to develop techniques that result in veliger mortality but do not harm fish. In September 2012, we conducted laboratory trials to determine if a molluscicide (750 mg/L potassium chloride and 25 mg/L formalin) commonly used to kill zebra mussel (Dreissena polymorpha) veligers in hatchery trucks can also effectively kill Asian clam veligers. We exposed Asian clam veligers to this molluscicide for 1, 3, and 5 h in each of two water types: deionized water and filtered lake water. We found ,20% mortality at the 1-h exposure period and 100% mortality at both the 3-h and 5-h exposure periods, regardless of water type. This laboratory study represents an important step toward reducing the spread of Asian clams by aquaculture facilities.

  19. Effect of Surface Preparation on CLAM/CLAM Hot Isostatic Pressing diffusion bonding joints

    Science.gov (United States)

    Li, C.; Huang, Q.; Zhang, P.

    2009-04-01

    Surface preparation is essential for the Hot Isostatic Pressing (HIP) diffusion bonding of RAFM steels. Hot Isostatic Pressing (HIP) diffusion bonding experiments on China Low Activation Martensitic (CLAM) steel was performed to study the effect of surface preparation. A few approaches such as hand lapping, dry-milling and grinding etc., were used to prepare the faying surfaces of the HIP joints. Different sealing techniques were used as well. The HIP parameters were 150 MPa/3 h/1150 °C. After post HIP heat treatment (PHHT), the tensile and Charpy impact tests were carried out. The results showed that hand lapping was not suitable to prepare the faying surfaces of HIP diffusion bonding specimens although the surface roughness by hand lapping was very low.

  20. Development status of CLAM steel for fusion application

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Qunying, E-mail: qunying.huang@fds.org.cn

    2014-12-15

    The China low activation martensitic (CLAM) steel is being developed at the Institute of Nuclear Energy Safety Technology (INEST) under wide collaboration within China. Significant R and D work on CLAM steel was carried out to help make it suitable for industrial applications. The effect of refining processes and thermal aging on composition, microstructures and mechanical properties were investigated. Material properties before irradiation including impact, fracture toughness, thermal aging, creep and fatigue properties etc. were assessed. A series of irradiation tests in the fission reactor HFETR in Chengdu up to 2 dpa and in the spallation neutron source SINQ in Paul Scherrer Institute up to 20 dpa were performed. PbLi corrosion tests for more than 10,000 h were done in the DRAGON-I and PICOLO loops. Fabrication techniques for a test blanket module (TBM) are being developed and a 1/3 scale TBM prototype is being fabricated with CLAM steel. Recent progresses on the development status of this steel are presented here. The code qualification of CLAM steel is under plan for its final application in ITER-TBM and DEMO in the future.

  1. Ancient clam gardens, traditional management portfolios, and the resilience of coupled human-ocean systems

    Directory of Open Access Journals (Sweden)

    Julia Jackley

    2016-12-01

    Full Text Available Indigenous communities have actively managed their environments for millennia using a diversity of resource use and conservation strategies. Clam gardens, ancient rock-walled intertidal beach terraces, represent one example of an early mariculture technology that may have been used to improve food security and confer resilience to coupled human-ocean systems. We surveyed a coastal landscape for evidence of past resource use and management to gain insight into ancient resource stewardship practices on the central coast of British Columbia, Canada. We found that clam gardens are embedded within a diverse portfolio of resource use and management strategies and were likely one component of a larger, complex resource management system. We compared clam diversity, density, recruitment, and biomass in three clam gardens and three unmodified nonwalled beaches. Evidence suggests that butter clams (Saxidomus gigantea had 1.96 times the biomass and 2.44 times the density in clam gardens relative to unmodified beaches. This was due to a reduction in beach slope and thus an increase in the optimal tidal range where clams grow and survive best. The most pronounced differences in butter clam density between nonwalled beaches and clam gardens were found at high tidal elevations at the top of the beach. Finally, clam recruits (0.5-2 mm in length tended to be greater in clam gardens compared to nonwalled beaches and may be attributed to the addition of shell hash by ancient people, which remains on the landscape today. As part of a broader social-ecological system, clam garden sites were among several modifications made by humans that collectively may have conferred resilience to past communities by providing reliable and diverse access to food resources.

  2. Change in metallothionein phosphorylation state in Mya arenaria clams: implication in metal metabolism and oxidative stress

    OpenAIRE

    Gagné, F.; M Gélinas; Gagnon, C.; André, C.; C Blaise

    2010-01-01

    The contamination of the benthic environment poses a threat to long-lived sessile organisms such as clams. The purpose of this study was to investigate metal contamination in tissues and changes in metallothioneins (MT) in respect to its redox status in Mya arenaria clams collected at three polluted sites. The phosphorylation state of MT was also investigated to determine whether this state is changed in clams collected at heavy-metal contaminated site and its involvement in cytoprotective si...

  3. Domoic acid excretion in dungeness crabs, razor clams and mussels.

    Science.gov (United States)

    Schultz, Irvin R; Skillman, Ann; Woodruff, Dana

    2008-07-01

    Domoic acid (DA) is a neurotoxic amino acid produced by several marine algal species of the Pseudo-nitzschia (PN) genus. We studied the elimination of DA from hemolymph after intravascular (IV) injection in razor clams (Siliqua patula), mussels (Mytilus edulis) and Dungeness crabs (Cancer magister). Crabs were also injected with two other organic acids, dichloroacetic acid (DCAA) and kainic acid (KA). For IV dosing, hemolymph was repetitively sampled and DA concentrations measured by HPLC-UV. Toxicokinetic analysis of DA in crabs suggested most of the injected dose remained within hemolymph compartment with little extravascular distribution. This observation is in sharp contrast to results obtained from clams and mussels which exhibited similarly large apparent volumes of distribution despite large differences in overall clearance. These findings suggest fundamentally different storage and elimination processes are occurring for DA between bivalves and crabs.

  4. 50 CFR 17.45 - Special rules-snails and clams. [Reserved

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 2 2010-10-01 2010-10-01 false Special rules-snails and clams. 17.45 Section 17.45 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR... Special rules—snails and clams....

  5. Mercury accumulation in the clam, Galatea paradoxa (Born 1778) at the Volta estuary, Ghana.

    Science.gov (United States)

    Obirikorang, K A; Amisah, S; Adjei-Boateng, D; Madkour, H A; Otchere, F A

    2010-11-01

    The concentration of mercury in the tissues of the clam, Galatea paradoxa at in the Volta estuary, Ghana, were analysed over an 18-month period, from March 2008 to August 2009. The concentrations were well below the International Human Consumption Advisory Limit of THg (0.5 μg/g wet weight). The concentrations in the tissues of the different clam size classes were between 6 and 18 times lower than the WHO Safety Reference Standard. Variation in the mean mercury concentration in the different clam size classes was not significant (p > 0.05) for clams from Aveglo but were highly significant (p < 0.0001) for clams from Ada, indicating a possible effect of size on accumulation. G. paradoxa is therefore suitable for human consumption based on the WHO Safety Reference Standards.

  6. Biodeposition, respiration, and excretion rates of an introduced clam Mercenaria mercenaria in ponds with implications for potential competition with the native clam Meretrix meretrix in Shuangtaizi estuary, China

    Science.gov (United States)

    Zhang, Anguo; Yuan, Xiutang; Hou, Wenjiu; Li, Xiaodong; Zhao, Kai; Chen, Weixin; Su, Xiurong

    2016-05-01

    This study aimed to evaluate the potential impacts of an introduced clam Mercenaria mercenaria on estuarine ecosystem, and implications for the niche competition with a native clam Meretrix meretrix. The biodeposition, respiration, and excretion rates of M. mercenaria were determined seasonally using a sediment trap and a closed respirator in field. The biodeposition rates of M. mercenaria were 0.06-0.37 g/ (ind.·d), and the respiration rates were 0.31-14.66 mg/(ind.·d). The ammonia and phosphate excretion rates were 0.18-36.70 and 1.44-14.87 μg/(ind.·d), respectively. The hard clam M. mercenaria may discharge dry deposits up to 2.1×105 t, contribute 18.3 t ammonia and 9.0 t phosphate to culture ponds, and consume 7.9×103 t O2 from ponds annually. It suggested that the hard clam M. mercenaria might play an important role in pelagic-benthic coupling in pond ecosystem through biodeposition and excretion. A comparison of the key physiological parameters of the introduced clam M. mercenaria and the native clam Meretrix meretrix suggested that M. mercenaria had a niche similar to that of Meretrix meretrix in Shuangtaizi estuary and might have a potential competition with Meretrix meretrix for habitat and food if M. mercenaria species escaped from the culture pond or artificially released in estuarine ecosystem.

  7. Protective role of edible clam Paphia malabarica (Chemnitz) against lipid peroxidation and free radicals

    Digital Repository Service at National Institute of Oceanography (India)

    Pawar, R.T.; Nagvenkar, S.S.; Jagtap, T.G.

    Kumar MNV. Role of antioxidants in prophylaxis and therapy: A phar- maceutical prospective. J. Control. Release 2006; 113:189-207. [42] Conners DE. Biomarkers of oxidative stress in freshwater clams (Corbicula fluminea) as mechanistic tools to evaluate...

  8. Population characteristics of the mangrove clam Polymesoda (geloina) erosa (solander, 1786) in the Chorao mangrove, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, B.S.; Naik, S.; Furtado, R.; Ansari, Z.A.; Chatterji, A.

    in the Indo-Pacific region. This unique but fragile ecosystem has been providing firewood, charcoal, pole, tannin and some traditional medicine to the people of coastal areas. Edible marine bivalves (clams, mussels and oysters) are widely distributed and form...

  9. Biodiesel Production from Castor Oil by Using Calcium Oxide Derived from Mud Clam Shell

    Directory of Open Access Journals (Sweden)

    S. Ismail

    2016-01-01

    Full Text Available The catalytic potential of calcium oxide synthesized from mud clam shell as a heterogeneous catalyst for biodiesel production was studied. The mud clam shell calcium oxide was characterized using particle size analyzer, Fourier transform infrared spectroscopy, scanning electron microscopy, and BET gas sorption analyzer. The catalyst performance of mud clam shell calcium oxide was studied in the transesterification of castor oil as biodiesel. Catalyst characterization and transesterification study results of synthesized catalyst proved the efficiency of the natural derived catalyst for biodiesel production. A highest biodiesel yield of 96.7% was obtained at optimal parameters such as 1 : 14 oil-to-methanol molar ratio, 3% w/w catalyst concentration, 60°C reaction temperature, and 2-hour reaction time. Catalyst reusability test shows that the synthesized calcium oxide from mud clam shell is reusable up to 5 times.

  10. Geographic distribution of mercury in asiatic clams, Corbicuia plumihea, from the North Fork Holston River, Virginia

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A study was conducted quantifying mercury concentrations in the Asiatic clam, Corbicula fluminea, from the North Fork Holston River, Virginia. The purpose of this...

  11. Contaminant assessment of fish, rangia clams, and sediments in the Lower Pamlico River, North Carolina

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Samples of sediment, rangia clams (Rangia cuneata), gizzard shad (Dorosoma cepedianum), and longnose gar (Lepisosteus osseus) were collected from five sites in the...

  12. Population Dynamics of the Giant Clam, Tridacna maxima, at Rose Atoll

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — There is a paucity of knowledge on the population dynamics of the giant clams of the family Tridacnidae. Such information on population dynamics is necessary for...

  13. Fisheries ecology: hunger for shark fin soup drives clam chowder off the menu.

    Science.gov (United States)

    Brierley, Andrew S

    2007-07-17

    Removal by fishing of large sharks has reduced predation-pressure on shark prey and, via a trophic cascade, caused clam populations to crash. This indirect response illustrates why fisheries should be managed in a whole-ecosystem context.

  14. Environmental context and trophic trait plasticity in a key species, the tellinid clam Macoma balthica L

    DEFF Research Database (Denmark)

    Törnroos, Anna; Nordström, M. C.; Aarnio, K.;

    2015-01-01

    showing differing isotopic signatures from clams at their original habitat, over time mirroring the changes in clams in the site to which they were transferred. The shift in carbon and nitrogen stable isotopes of the clams provides insights into the context-dependent intraspecific feeding plasticity......Species show varying levels of plasticity regarding morphology, physiology and behaviour in relation to their immediate environment, and several trait characteristics are habitat-dependent. Determining when and how the environmental context changes trait expression is of key importance...... food uptake by using stable isotope signatures (delta C-13 and delta N-15). We transplanted individuals between and within two shallow bays differing in exposure (exposed sheltered) and sediment characteristics. Our results show that isotope signatures of clams differed between the two habitats...

  15. Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (South Atlantic) Hard Clam,

    Science.gov (United States)

    1987-08-01

    nearby and lead to the aggregated that attaches to the substrate by distribution of clams. means of a byssus (Carriker 1961). When larvae settle, they...have better byssus gland (Belding 1912), the conditions for spat survival than un- active development of siphons and structured bottoms - probably...1961). The foot shortens and the greater numbers of juvenile hard clams byssus gland becomes nonfunctional. than control areas (Parker 1975). Ex

  16. Ionic and Amino Acid Regulation in Hard Clam (Meretrix lusoria in Response to Salinity Challenges

    Directory of Open Access Journals (Sweden)

    Chia-Hao Lin

    2016-08-01

    Full Text Available Most marine mollusks are osmoconformers, in that, their body fluid osmolality changes in the direction of the change in environmental salinity. Marine mollusks exhibit a number of osmoregulatory mechanisms to cope with either hypo- or hyperosmotic stress. The effects of changes in salinity on the osmoregulatory mechanisms of the hard clam (Meretrix lusoria, an economically important species of marine bivalve for Taiwan have not been determined. In this study, we examined the effect of exposure to hypo (10‰- and hyper (35‰-osmotic salinity on hard clams raised at their natural salinity (20‰. The osmolality, [Na+], and [Cl-] of the hard clam hemolymph were changed in the same direction as the surrounding salinity. Further, the contents of total free amino acids including taurine in the gills and mantles were significantly upregulated in hard clam with increasing salinity. The gill Na+,K+-ATPase (NKA activity, the important enzyme regulating cellular inorganic ions, was not affected by the changed salinity. Mantle NKA activity, however, was stimulated in the 35‰ SW treatment. The taurine transporter (TAUT is related to the regulation of intracellular contents of taurine, the dominant osmolyte. Herein, a TAUT gene of hard clam was cloned and a TAUT antibody was derived for the immunoblotting. The TAUT mRNA expression of the mantle in hard clam was significantly stimulated in 35‰ SW, but protein expression was not modulated by the changed salinity. In gills of the hard clam with 10‰ SW, both TAUT mRNA and protein expressions were significantly stimulated, and it may reflect a feedback regulation from the decreased gills taurine content under long-term hypoosmotic acclimation. These findings suggest that TAUT expression is regulated differently in gills and mantles following exposure to alterations in environmental salinity. Taken together, this study used the physiological, biochemical and molecular approaches to simultaneously explore

  17. Ionic and Amino Acid Regulation in Hard Clam (Meretrix lusoria) in Response to Salinity Challenges.

    Science.gov (United States)

    Lin, Chia-Hao; Yeh, Po-Ling; Lee, Tsung-Han

    2016-01-01

    Most marine mollusks are osmoconformers, in that, their body fluid osmolality changes in the direction of the change in environmental salinity. Marine mollusks exhibit a number of osmoregulatory mechanisms to cope with either hypo- or hyperosmotic stress. The effects of changes in salinity on the osmoregulatory mechanisms of the hard clam (Meretrix lusoria, an economically important species of marine bivalve for Taiwan) have not been determined. In this study, we examined the effect of exposure to hypo (10‰)- and hyper (35‰)-osmotic salinity on hard clams raised at their natural salinity (20‰). The osmolality, [Na(+)], and [Cl(-)] of the hard clam hemolymph were changed in the same direction as the surrounding salinity. Further, the contents of total free amino acids including taurine in the gills and mantles were significantly upregulated in hard clam with increasing salinity. The gill Na(+), K(+)-ATPase (NKA) activity, the important enzyme regulating cellular inorganic ions, was not affected by the changed salinity. Mantle NKA activity, however, was stimulated in the 35‰ SW treatment. The taurine transporter (TAUT) is related to the regulation of intracellular contents of taurine, the dominant osmolyte. Herein, a TAUT gene of hard clam was cloned and a TAUT antibody was derived for the immunoblotting. The TAUT mRNA expression of the mantle in hard clam was significantly stimulated in 35‰ SW, but protein expression was not modulated by the changed salinity. In gills of the hard clam with 10‰ SW, both TAUT mRNA and protein expressions were significantly stimulated, and it may reflect a feedback regulation from the decreased gills taurine content under long-term hypoosmotic acclimation. These findings suggest that TAUT expression is regulated differently in gills and mantles following exposure to alterations in environmental salinity. Taken together, this study used the physiological, biochemical and molecular approaches to simultaneously explore the

  18. Immune- and Pollution-mediated DNA Damage in Two Wild Mya arenaria Clam Populations

    OpenAIRE

    François Gagné; M. Laura Martín-Díaz; Christian Blaise

    2009-01-01

    In aquatic environments, genotoxicity results from the effects of pollution combined with the inflammatory response triggered by the immune system. Indeed, the production of nitrosylated DNA and proteins are though to arise from the production of peroxinitrite during phagocytosis and inflammation. The purpose of this study was to examine new DNA biomarkers that differentiate between immune- and pollution-mediated genotoxicity in wild clam populations. Intertidal clam populations were sampled ...

  19. Growth and survival of endangered angelwing clam, Pholas orientalis fed different algal diets

    Directory of Open Access Journals (Sweden)

    M. Shirley M. Golez

    2011-12-01

    Full Text Available Mature angelwing clam, Pholas orientalis were collected from the wild and transported tothe laboratory for broodstock development. They were fed with mixed algal cultures of Isochrysisgalbana, Chaetoceros sp., and Tetraselmis sp. for a period of two months and a half to determine theeffects of these algal cultures on growth and survival of the broodstock. Growth in terms of length wasnot significantly different among the treatment groups, whereas, there was significant reduction in theweight of the clams in the group fed with a mixture of Isochrysis galbana, Chaetoceros sp., andTetraselmis sp. Survival of the clams decreased after two months of feeding with algal diets, withsignificant mortality observed in groups fed with a mixture of Isochrysis galbana and Tetraselmis sp. aswell as with the mixture of the three microalgae. All the water quality parameters in the rearing tankswere within the optimum levels required for optimum growth of the clams. These results showed thatmixed algal diets for broodstock development in angelwing clam have no direct effect on growth butmoderate effect on survival. Future studies are aimed towards determining other factors that willcontribute to better growth and survival of angelwing clam broodstock in captivity as well as for thesearch of alternative algal diets for angelwing broodstock, particularly by exploring the microalgae thatare found in their natural habitat.

  20. REVIEW: Symbiosis between the Giant Clams (Bivalvia: Cardiidae and Zooxanthellae (Dinophyceae

    Directory of Open Access Journals (Sweden)

    UDHI EKO HERNAWAN

    2008-01-01

    Full Text Available Giant clams are the largest bivalves in the world that maintain a mutual relationship with zooxanthellae. Individual giant clam can harbor heterogeneous zooxanthellae, at least four taxa in genus Symbiodinium. The Symbiodinium lives in the zooxanthellal tubular system, a tube structure arising from one of the diverticular duct of the clam’s stomach. Since the numbers of zooxanthellae is the one of some significant factors contributing to the clams growth and survival, the giant clams need to adjust the number of zooxanthellae for physiological reason with unclear mechanism. The important role of the symbiotic relationship to the clams can be seen on the survival, growth and nutrition of the clams. There are at least two significant factors determining the symbiosis, i.e. water temperature in related with level of light intensities and ammonium-phosphate rate. Some topic is still unclear, i.e. the determination of species in genus Symbiodinium, the mechanism for adjusting the population numbers of the algae and what kind of environmental factors determining the symbiosis. Thereby further research is still needed to clarify those missing.

  1. Dimethylsulfoniopropionate in six species of giant clams and the evolution of dimethylsulfide after death

    Energy Technology Data Exchange (ETDEWEB)

    Hill, R.W.; Hill, S.D. [Michigan State Univ., East Lansing, MI (United States). Dept. of Zoology; Dacey, J.W.H. [Woods Hole Oceanographic Inst., Woods Hole, MA (United States). Dept. of Biology; Edward, A. [Micronesia College, Pohnpei (Micronesia, Federated States); Hicks, W.A. [Michigan State Univ., East Lansing, MI (United States). Dept. of Bioichemistry and Molecular Biology

    2004-05-01

    Dimethylsulfoniopropionate (DMSP) could accumulate in large concentrations in animals living symbiotically with algae. The giant clam family Tridacnidae accumulates DMSP because they have a symbiotic relationship with dinoflagellates (or zooxanthellae). In this study, well preserved clam tissues from the western Pacific Islands were analyzed to provide definitive evidence of DMSP in the tissues. Six of the common species in the Tridacnidae family were examined. The objective was to test the hypothesis that dimethyl sulfide (DMS) is released from clam tissues soon after death due to the breakdown of DMSP tissue. In particular, it determined if DMS is responsible for the problem of potent odours and off-taste that have hindered the commercial success of giant clams mariculture. Gas chromatography and mass spectrometry was used in this study to measure DMSP concentrations in siphonal mantle, byssal mantle, adductor muscle and gill tissues. The formation of DMS by tissues after death was documented. It was suggested that since giant clams associate with dinoflagellates, they could accumulate DMSP to high concentrations which could affect multiple properties and functions. It was concluded that the perishability of giant clam tissues is most likely due to the high concentrations of DMS produced one day post mortem. 15 refs., 2 tabs., 4 figs.

  2. Empirical Analysis of the Typical Breeding Pattern of Clam in Hongdao Town and the Preliminary Estimates of Costs and Benefits

    Institute of Scientific and Technical Information of China (English)

    Xijuan; YANG; Shijun; ZHANG

    2014-01-01

    Based on the survey data about clam breeding farmers in Hongdao Town in August 2011,this paper analyzes the production and operation of typical clam breeding pattern,and estimates the costs and benefits. Through the analysis of operation conditions and economic conditions of Hongdao clam breeding,this paper aims to explore a more reasonable and effective breeding pattern so as to reduce breeding costs and market risks,and increase breeding farmers’ income.

  3. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic). HARD CLAM.

    Science.gov (United States)

    1985-02-01

    days at 30’C (Loosanoff et al. comm.). 1951). To move, the clam byssus is cast Juvenile Seed Clam off and the foot is used for locomo- tion (Belding...1931). When the young When the veliger becomes 0.2 to clam reaches a desirable habitat, it 0.3 mm long, the shell thickens, a spins a new byssus and...currents (Anderson et The byssal gland of the seed clam al. 1979), but in the absence of secretes a tough thread, the byssus , predators, Carriker (1959

  4. Understanding the Use-wears on Non-retouched Shells Mytilus galloprovincialis. and Ruditapes decussatus by Performing Wood Working Experiment: An Experimental Approach

    Science.gov (United States)

    Tumung, Laxmi; Bazgir, Behrouz; Ahmadi, Kamran; Shadmehr, Abdolkarim

    2012-07-01

    This paper is an experimental attempt to understand the use-wear comes on non-retouched shells Ruditapes decussatus and Mytilus galloprovincialis. These species have been selected due to their variation in shape, size and edge type. In wood working experiment Celtus australis wood is used to perform the activities like scrapping and cutting wood. The ESEM results show the usewears in the form of linear marks, edge rounding, edge facture, polish and micro-pitting. Experiments also showed some macro-fractures.

  5. Change in metallothionein phosphorylation state in Mya arenaria clams: implication in metal metabolism and oxidative stress

    Directory of Open Access Journals (Sweden)

    F Gagné

    2010-01-01

    Full Text Available The contamination of the benthic environment poses a threat to long-lived sessile organisms such as clams. The purpose of this study was to investigate metal contamination in tissues and changes in metallothioneins (MT in respect to its redox status in Mya arenaria clams collected at three polluted sites. The phosphorylation state of MT was also investigated to determine whether this state is changed in clams collected at heavy-metal contaminated site and its involvement in cytoprotective signaling during stress contamination. The results show that clams collected at least one of the three polluted sites presented significantly higher concentrations of silver (Ag, arsenic (As, cobalt (Co, copper (Cu, mercury (Hg, nickel (Ni, tin (Sn and lead (Pb in tissues. In the visceral tissue, total MT levels and the reduced, metal-binding form of the protein were significantly induced at the sites. The phosphorylation of MT and mitochondrial activity, as determined by electron transport and cytochrome c oxidase activities, were also significantly reduced at the contaminated sites. Reduced phosphate levels in MT were negatively correlated with total MT levels, suggesting that decreased phosphorylation was involved in kinase-mediated signaling during cellular stress and could possibly alter the protein’s affinity to confer cytoprotection against heavy metal contamination. These preliminary investigations revealed that the phosphorylation state could change in polluted environment and provide some clues on the modulation of binding affinities during heavy-metal and oxidative stress in clams.

  6. Immune- and Pollution-mediated DNA Damage in Two Wild Mya arenaria Clam Populations

    Directory of Open Access Journals (Sweden)

    François Gagné

    2009-01-01

    Full Text Available In aquatic environments, genotoxicity results from the effects of pollution combined with the inflammatory response triggered by the immune system. Indeed, the production of nitrosylated DNA and proteins are though to arise from the production of peroxinitrite during phagocytosis and inflammation. The purpose of this study was to examine new DNA biomarkers that differentiate between immune- and pollution-mediated genotoxicity in wild clam populations. Intertidal clam populations were sampled and analyzed for gonadal DNA strand breaks, DNA nitrosylation and xanthine oxidoreductase (XOR activity (purine salvage pathway. The clam weight-to-shell-length ratio, the gonado-somatic index (GSI, age status, lipid peroxidation, xenobiotic conjugation activity (glutathione S-transferase (GST and phagocytic activity were examined to shed light on their relationships with the observed genotoxic endpoints. XOR activity and DNA strand breaks were generally elevated at polluted sites and correlated significantly with clam weight-to-shell-length ratios and DNA nitrosylation. DNA nitrosylation was also higher at some sites and correlated significantly with phagocytic activity and with DNA strand breaks. This study showed that DNA strand breaks were associated with both immune- and pollution-mediated effects. This suggests that there is a loss of DNA repair capacity due to the combined effects of aging, pollution and immune response in wild clam populations that are impacted by anthropogenic activity.

  7. Aquaculture Land-Use Policy: The Case of Clam Farming in Thaibinh Province, Vietnam

    Directory of Open Access Journals (Sweden)

    Thi Thu Hang NGO

    2016-12-01

    Full Text Available Policy-making and enforcement remains centralized in Vietnam. Policies have been formulated with less scientific and public justification, thus being largely bureaucratic and infeasible, and in many cases, they have created plagues for people at the grass-roots levels. This article focuses on the implementation of policies related to intertidal land-use and supports for clam farming in the Thaibinh province as a case study to explore the impacts of policies on clam farming and farmers. During the period of 2011–2013, provincial policies on intertidal land allocation and technical and financial supports had boosted clam farming development in the province to a surprising extent. Rapid expansion of the clam farming area has created significant consequences for the farming sector, as well as farmer’s lives. However, for the same provincial policies, but with different enforcement, different farming outcomes for clam farmers in the three study communes have resulted. Where farmers had more of a voice and choice in bidding for the intertidal areas they preferred, they faced fewer problems. It is, thus, suggested that a more decentralized policy-making and enforcement are needed, in which more scientific assessment and farmer participation are required to not only make government policy more successful in supporting farmers and achieving their expected outcomes, but also to provide farmers with more room to make their own farming decisions from which farming and marketing risks could be mitigated.

  8. Quantitative modeling for risk assessment of Vibrio parahaemolyticus in bloody clams in southern Thailand.

    Science.gov (United States)

    Yamamoto, Akio; Iwahori, Jun'ichiro; Vuddhakul, Varaporn; Charernjiratragul, Wilawan; Vose, David; Osaka, Ken; Shigematsu, Mika; Toyofuku, Hajime; Yamamoto, Shigeki; Nishibuchi, Mitsuaki; Kasuga, Fumiko

    2008-05-10

    A risk assessment of Vibrio parahaemolyticus in bloody clams (Anadara granosa) consumed in southern Thailand was conducted. This study estimated the prevalence and concentration of pathogenic V. parahaemolyticus in bloody clams at harvest and retail stages; and during this process, methods to detect the total and pathogenic V. parahaemolyticus were investigated. Consumption of bloody clams and cooking efficiency were studied using interviews and on-site observation of consumers. A beta-Poisson dose-response model was used to estimate probability of illness applying estimation methods for the most likely parameter values presented by USFDA. Microbial and behavioral data were analyzed by developing a stochastic model and the simulation gave a mean number of times a person would get ill with V. parahaemolyticus by consuming bloody clams at 5.6 x 10(-4)/person/year. Sensitivity analysis demonstrated the fraction of people who did not boil the clams properly was the primary factor in increasing risk. This study serves as an example of how a microbiological risk assessment with limited data collection and international cooperation leads to valuable local insight.

  9. Impediment to Symbiosis Establishment between Giant Clams and Symbiodinium Algae Due to Sterilization of Seawater

    Science.gov (United States)

    Kurihara, Takeo; Yamada, Hideaki; Inoue, Ken; Iwai, Kenji; Hatta, Masayuki

    2013-01-01

    To survive the juvenile stage, giant clam juveniles need to establish a symbiotic relationship with the microalgae Symbiodinium occurring in the environment. The percentage of giant clam juveniles succeeding in symbiosis establishment (“symbiosis rate”) is often low, which is problematic for seed producers. We investigated how and why symbiosis rates vary, depending on whether giant clam seeds are continuously reared in UV treated or non treated seawater. Results repeatedly demonstrated that symbiosis rates were lower for UV treated seawater than for non treated seawater. Symbiosis rates were also lower for autoclaved seawater and 0.2-µm filtered seawater than for non treated seawater. The decreased symbiosis rates in various sterilized seawater suggest the possibility that some factors helping symbiosis establishment in natural seawater are weakened owing to sterilization. The possible factors include vitality of giant clam seeds, since additional experiments revealed that survival rates of seeds reared alone without Symbiodinium were lower in sterilized seawater than in non treated seawater. In conclusion, UV treatment of seawater was found to lead to decreased symbiosis rates, which is due possibly to some adverse effects common to the various sterilization techniques and relates to the vitality of the giant clam seeds. PMID:23613802

  10. Blastopirellula cremea sp. nov., isolated from a dead ark clam.

    Science.gov (United States)

    Lee, Hae-Won; Roh, Seong Woon; Shin, Na-Ri; Lee, Jina; Whon, Tae Woong; Jung, Mi-Ja; Yun, Ji-Hyun; Kim, Min-Soo; Hyun, Dong-Wook; Kim, Daekyung; Bae, Jin-Woo

    2013-06-01

    Strain LHWP2(T), a novel, aerobic, budding, motile and ovoid bacterium belonging to the phylum Planctomycetes, was isolated from a dead ark clam (Scapharca broughtonii) from the south coast of Korea. Strain LHWP2(T) grew optimally at 30 °C, in the presence of 4% (w/v) NaCl, and at pH 7. The predominant cellular fatty acids were C16:0, C18:1ω7c and/or C18:1ω6c (summed feature 8) and C18:1ω9c. The major isoprenoid quinone was menaquinone-6 (MK-6). The dominant polar lipid was identified as phosphatidylglycerol. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the novel strain was most closely related to Blastopirellula marina DSM 3645(T), with a 16S rRNA gene sequence similarity of 94.1%. The genomic DNA G+C content of strain LHWP2(T) was 49.5 mol%. Strain LHWP2(T) was distinguished from B. marina DSM 3645(T) based on its optimum salinity, acid production from substrates, assimilation of substrates and DNA G+C content. Overall, these phenotypic, genotypic and phylogenetic data suggest that strain LHWP2(T) should be classified as a novel species belonging to the genus Blastopirellula, for which the name Blastopirellula cremea sp. nov. is proposed. The type strain is LHWP2(T) (=KACC 15559(T)=JCM 17758(T)).

  11. Ornithinibacillus scapharcae sp. nov., isolated from a dead ark clam.

    Science.gov (United States)

    Shin, Na-Ri; Whon, Tae Woong; Kim, Min-Soo; Roh, Seong Woon; Jung, Mi-Ja; Kim, Young-Ok; Bae, Jin-Woo

    2012-01-01

    A novel Gram-positive, aerobic, motile, hemolytic, endospore-forming and rod-shaped bacterium TW25(T) was isolated from a dead ark clam during a mass mortality event on the South coast of Korea. The strain grew optimally at 30°C, at pH 8-9, and with 1% (w/v) NaCl. The 16S rRNA gene sequence analysis indicated that strain TW25(T) was associated with the genus Ornithinibacillus and that it was most closely related to the type strain of Ornithinibacillus californiensis (98.5% similarity). The dominant cellular fatty acids were iso-C15:0, anteiso-C15:0 and C16:0. The peptidoglycan amino acid type was A4β, containing L: -ornithine and D: -aspartic acid. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, four unidentified phospholipids, two unidentified aminolipids and two unidentified lipids. The major respiratory quinone was menaquinone-7 (MK-7). The G + C content of genomic DNA was 36.7 mol%. DNA-DNA hybridization experiments with related strains revealed lower than 11 ± 3% relatedness. Based on this polyphasic taxonomic study, strain TW25(T) represents a novel species in the genus Ornithinibacillus, for which the name Ornithinibacillus scapharcae sp. nov. is proposed. The type strain is TW25(T) (=KACC 15116(T) = JCM 17314(T)).

  12. Lethal effects on different marine organisms, associated with sediment-seawater acidification deriving from CO2 leakage.

    Science.gov (United States)

    Basallote, M D; Rodríguez-Romero, A; Blasco, J; DelValls, A; Riba, I

    2011-08-01

    CO(2) leakages during carbon capture and storage in sub-seabed geological structures could produce potential impacts on the marine environment. To study lethal effects on marine organisms attributable to CO(2) seawater acidification, a bubbling CO(2) system was designed enabling a battery of different tests to be conducted, under laboratory conditions, employing various pH treatments (8.0, 7.5, 7.0, 6.5, 6.0, and 5.5). Assays were performed of three exposure routes (seawater, whole sediment, and sediment elutriate). Individuals of the clam (Ruditapes philippinarum) and early-life stages of the gilthead seabream, Sparus aurata, were exposed for 10 days and 72 h, respectively, to acidified clean seawater. S. aurata larvae were also exposed to acidified elutriate samples, and polychaete organisms of the specie Hediste diversicolor and clams R. philippinarum were also exposed for 10 days to estuarine whole sediment. In the fish larvae elutriate test, 100 % mortality was recorded at pH 6.0, after 48 h of exposure. Similar results were obtained in the clam sediment exposure test. In the other organisms, significant mortality (p < 0.05) was observed at pH values lower than 6.0. Very high lethal effects (calculating L[H(+)]50, defined as the H(+) concentration that causes lethal effects in 50 % of the population exposed) were detected in association with the lowest pH treatment for all the species. The implication of these results is that a severe decrease of seawater pH would cause high mortality in marine organisms of several different kinds and life stages. The study addresses the potential risks incurred due to CO(2) leakages in marine environments.

  13. High cycle fatigue properties of CLAM steel at 723 K and 823 K

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yanyun; Zhai, Xiangwei; Liu, Shaojun, E-mail: shaojun.liu@fds.org.cn; Li, Chunjing; Huang, Qunying

    2015-11-15

    Highlights: • High cycle fatigue properties of CLAM steel were investigated at 723 K and 823 K. • The condition fatigue limit at N = 10{sup 7} were 275 MPa and 235 MPa at 723 K and 823 K. • Fatigue strength decreased when stress and temperature increased at 723 K and 823 K. • Dislocation density decrease and subgrain coarsening during the test process were the possible reasons for fatigue limit decrease. - Abstract: This paper highlights the results of a study on the high cycle fatigue strength and fracture mechanism of China Low Activation Martensitic (CLAM) steel. The high cycle fatigue test results showed that the fatigue strength of CLAM steel decreased with the temperature, and the condition fatigue strengths (N = 10{sup 7}) were 275 MPa and 235 MPa at 723 K and 823 K, respectively. The fractograph results indicated that the fractures were mainly initiated from the surface of the specimen.

  14. Effect of coastal eutrophication on heavy metal bioaccumulation and oral bioavailability in the razor clam, Sinonovacula constricta

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Tengxiu [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Li, Shunxing, E-mail: lishunxing@mnnu.edu.cn [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology (China); Chen, Lihui [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Zheng, Fengying; Huang, Xu-Guang [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology (China)

    2014-10-15

    Graphical abstract: - Highlights: • Razor clams are often exposed to coastal eutrophication. • The bioaccumulation of Fe, Ni, V, and As was promoted by eutrophication. • Bionic gastrointestinal tract was used for metal oral bioavailability assessment. • Eutrophication decreased oral bioavailability of Fe and Pb but enhanced for V. • The daily maximum allowable intakes are controlled by eutrophication levels. - Abstract: As traditional seafoods, the razor clams are widely distributed from tropical to temperate areas. Coastal razor clams are often exposed to eutrophication. Heavy metal contamination is critical for seafood safety. However, how eutrophication affects bioaccumulation and oral bioavailability of heavy metals in the razor clams is unknown. After a four-month field experimental cultivation, heavy metals (Fe, Cu, Ni, V, As, and Pb) could be bioaccumulated by the razor clams (Sinonovacula constricta) through exposure to metals present in water and sediments or in the food chain, and then transferred to human via consumption of razor clams. Bionic gastrointestinal digestion and monolayer liposome extraction are used for metal oral bioavailability (OBA) assessment. The influence of eutrophication on OBA is decreased for Fe and Pb and increased for V. A significant positive linear correlation was observed between the bioaccumulation factors of Fe, Ni, V, and As in razor clams and the coastal eutrophication. These results may be due to the effect of eutrophication on metal species transformation in coastal seawater and subcellular distribution in razor clams. The maximum allowable daily intakes of razor clams are controlled by eutrophication status and the concentration of affinity-liposome As in razor clams.

  15. Microstructure and nanoindentation of the CLAM steel with nanocrystalline grains under Xe irradiation

    Science.gov (United States)

    Chang, Yongqin; Zhang, Jing; Li, Xiaolin; Guo, Qiang; Wan, Farong; Long, Yi

    2014-12-01

    This work presents an early look at irradiation effects on China low activation martensitic (CLAM) steel with nanocrystalline grains (NC-CLAM steels) under 500 keV Xe-ion bombardment at room temperature to doses up to 5.3 displacements per atom (dpa). The microstructure in the topmost region of the steel is composed of nanocrystalline grains with an average diameter of 13 nm. As the samples were implanted at low dose, the nanocrystalline grains had martensite lath structure, and many dislocations and high density bubbles were introduced into the NC-CLAM steels. As the irradiation dose up to 5.3 dpa, a tangled dislocation network exists in the lath region, and the size of the bubbles increases. X-ray diffraction results show that the crystal quality decreases after irradiation, although the nanocrystals obviously coarsen. Grain growth under irradiation may be ascribed to the direct impact of the thermal spike on grain boundaries in the NC-CLAM steels. In irradiated samples, a compressive stress exists in the surface layer because of grain growth and irradiation-introduced defects, while the irradiation introduced grain-size coarsening and defects gradients from the surface to matrix result in a tensile stress in the irradiated NC-CLAM steels. Nanoindentation was used to estimate changes in mechanical properties during irradiation, and the results show that the hardness of the NC-CLAM steels increases with increasing irradiation dose, which was ascribed to the competition between the grain boundaries and the irradiation-introduced defects.

  16. Fluorescent amplified fragment length polymorphism (fAFLP)analysis of population genetic diversity and species relationships of four species of cultured clams in family Veneridae (Mollusca: Bivalvia)%帘蛤科4种养殖蛤群体遗传多样性和种间关系的fAFLP分析

    Institute of Scientific and Technical Information of China (English)

    彭永兴; 程汉良; 夏德全; 吴婷婷; 孟学平; 吉红九; 董志国

    2008-01-01

    利用荧光标记扩增片段长度多态性(fAFLP)技术对文蛤(Meretrix meretrix)、青蛤(Cyclina sinensis)、菲律宾蛤仔(Ruditapes philippinarum)和硬壳蛤(Mercenaria mercenaria)4种帘蛤科贝类的群体遗传多样性和种间关系进行了研究.选择EcoR Ⅰ/Mse Ⅰ进行酶切,使用6个E+3/M+3引物组合进行扩增,共获得1096个位点,多态位点比率95.1%,片段长度50~456 bp.其中,文蛤、青蛤、菲律宾蛤仔和硬壳蛤分别得到681,715,702和694个位点,相应的多态位点比率为76.8%,81.7%,83.0%和75.1%,得到17个种特异性位点,可作为4物种特征标记.分析了群体遗传相似系数和遗传多样性指数以及种间遗传相似系数.结果表明,硬壳蛤群体遗传相似系数最高(0.670 9),遗传多样性指数最低(0.236 0);菲律宾蛤仔群体遗传相似系数最低(0.592 5),遗传多样性指数最高(0.261 8);根据遗传相似系数采用UPGMA法构建了4物种32个体的聚类图,表明文蛤与菲律宾蛤仔遗传关系最近,青蛤与其他3物种遗传关系较远.

  17. Sequence analysis of mitochondrial COI gene fragment of six Veneridae clams ( Mollusca: Bivalvia) and four populations of Meretrix meretrix%6种帘蛤科贝类及4个地理种群文蛤线粒体COI基因片段序列分析

    Institute of Scientific and Technical Information of China (English)

    程汉良; 夏德全; 吴婷婷; 孟学平; 吉红九; 董志国; 陈淑吟

    2007-01-01

    对文蛤(Meretrix meretrix L,1758)、青蛤(Cyclina sinensis G.,1791)、硬壳蛤(Mercenaria mercenaria L,1758)、江户布目蛤(Protothaca jedoensis L,1874)、薄片镜蛤(Dosinia corrugata R.,1850)和菲律宾蛤仔(Ruditapes philippinarum A.,1850)6种帘蛤科贝类和4个地理种群文蛤(大连、连云港、湛江、防城港)的细胞色素c氧化酶亚基Ⅰ(COI)基因片段的核苷酸序列进行了分析,以探讨这一序列在种质鉴定、种群遗传结构和分子系统发生研究中的应用价值.测序结果表明,所有物种扩增片段长度均为709 bp,序列A+T含量(62.2%~67.6%)明显高于GC含量.物种间共有变异位点311个,其中简约信息位点202个;文蛤4个地理种群间共有变异位点46个,其中简约信息位点2个.此区段共编码235个氨基酸,种间共有氨基酸变异位点85个;文蛤种群间只有1个氨基酸变异位点.以COI基因片段序列为标记,用大竹蛏(Solen grandis)作外群,构建了帘蛤科贝类的系统发生树,其拓扑结构显示4个地理种群文蛤首先聚为1个单元,然后与青蛤聚在一起,最后所有帘蛤科物种聚为一枝,与外群相区别,其结果与传统形态分类基本一致,说明COI基因适合作为该科贝类种群遗传结构和系统发生研究的分子标记.

  18. Cadmium sulfide quantum dots induce oxidative stress and behavioral impairments in the marine clam Scrobicularia plana.

    Science.gov (United States)

    Buffet, Pierre-Emmanuel; Zalouk-Vergnoux, Aurore; Poirier, Laurence; Lopes, Christelle; Risso-de-Faverney, Christine; Guibbolini, Marielle; Gilliland, Douglas; Perrein-Ettajani, Hanane; Valsami-Jones, Eugenia; Mouneyrac, Catherine

    2015-07-01

    Cadmium sulfide (CdS) quantum dots have a number of current applications in electronics and solar cells and significant future potential in medicine. The aim of the present study was to examine the toxic effects of CdS quantum dots on the marine clam Scrobicularia plana exposed for 14 d to these nanomaterials (10 µg Cd L(-1) ) in natural seawater and to compare them with soluble Cd. Measurement of labile Cd released from CdS quantum dots showed that 52% of CdS quantum dots remained in the nanoparticulate form. Clams accumulated the same levels of Cd regardless of the form in which it was delivered (soluble Cd vs CdS quantum dots). However, significant changes in biochemical responses were observed in clams exposed to CdS quantum dots compared with soluble Cd. Increased activities of catalase and glutathione-S-transferase were significantly higher in clams exposed in seawater to Cd as the nanoparticulate versus the soluble form, suggesting a specific nano effect. The behavior of S. plana in sediment showed impairments of foot movements only in the case of exposure to CdS quantum dots. The results show that oxidative stress and behavior biomarkers are sensitive predictors of CdS quantum dots toxicity in S. plana. Such responses, appearing well before changes might occur at the population level, demonstrate the usefulness of this model species and type of biomarker in the assessment of nanoparticle contamination in estuarine ecosystems.

  19. Multidrug-resistant and epidemic clones of Escherichia coli from natural beds of Venus clam.

    Science.gov (United States)

    Vignaroli, C; Di Sante, L; Leoni, F; Chierichetti, S; Ottaviani, D; Citterio, B; Biavasco, F

    2016-10-01

    Epidemic Escherichia coli clones have been recovered in marine sediment along the coast of Marche, an Adriatic region in central Italy. In the present study, E. coli strains from the clam Chamelea gallina, sampled from seven natural beds in the same area, were detected. Selected E. coli isolates from all sampling sites were screened for antimicrobial susceptibility, genetic diversity and correlation. The majority (60%) belonged to phylogroups A or B1, 31% to the other groups (B2, C, D, E, F), 8% to cryptic clades, and 1% were untypable. Moreover, 33.3% of isolates were resistant to at least one drug and 11% were multidrug resistant (MDR). The most common resistance was to tetracycline, ampicillin, and streptomycin. No clonality was detected, but the strains' high genetic heterogeneity pointed at multiple sources of microbiological contamination. MLST analysis found potentially pathogenic and even epidemic MDR strains in clams collected in class A (ST746 and ST46) and class B (ST393, ST58 and ST131) areas, indicating that strains of clinical origin are detectable in clams. These data highlight that eating raw or lightly cooked clams may pose a health risk if purification is not performed or is ineffective.

  20. CLAM - CoLlAborative eMbedded networks for submarine surveillance: An overview

    NARCIS (Netherlands)

    Meratnia, Nirvana; Havinga, Paul J.M.; Casari, Paolo; Petrioli, Chiara; Grythe, Knut; Husoy, Thor; Zorzi, Michele

    2011-01-01

    This paper provides an overview of the CLAM project, which aims at developing a collaborative embedded monitoring and control platform for submarine surveillance by combining cutting edge acoustic vector sensor technology and 1D, 2D, 3D sensor arrays, underwater wireless sensor networks protocol des

  1. Genetic diversity of European populations of the invasive soft-shell clam Mya arenaria (Bivalvia)

    NARCIS (Netherlands)

    Lasota, R.; Hummel, H.; Wolowicz, M.

    2004-01-01

    The genetic diversity of the soft-shell clam Mya arenaria from seven locations in Europe (two stations in the southern Baltic Sea (the Gulf of Gdansk) and two in the North Sea (Veerse Meer and Oosterschelde), and three additional stations in the Denmark Straits and Bay of Biscay) was determined usin

  2. Recruitment of mud clam Polymesoda erosa (Solander, 1876) in a mangrove habitat of Chorao Island, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Clemente, S.; Ingole, B.S.

    of settling post-larvae was 28 no.m sup(-2) with a majority of settlers during Sept 04. The density of adult clams in the landward zone ranged from 7-12 no.m sup(-2) (mean: 9 + or - 6 sd; n=122). In the seaward region, adults were completely absent at the low...

  3. Effect of Epinephrine on the Settlement and Metamorphosis of Manila Clam Larvae

    Institute of Scientific and Technical Information of China (English)

    LU Sumin; BAO Zhenmin; LIU Hui; FANG Jianguang

    2006-01-01

    Chemical inducement and DDRT-PCR (differential display reverse transcription PCR) are adopted to investigate the effect of epinephrine (EPI) on the settlement and metamorphosis of Manila clam larvae. Chemical inducement shows that EPI has an effect to some extent on the metamorphosis of Manila clam larvae at all concentrations and in all treatments designed. The most significant result of inducement is obtained at the concentration of 10-6 molL-1 and for 4 h. DDRT-PCR using six primer pairs shows that the gene expression pattern is quite different between EPI treatment and the control. Three hundred and forty-three amplification bands are obtained in total, among which, 67 (19.53%) are differentially appeared.Therefore, EPI has an effect on the gene expression of the eye spot larval Manila clam. It can be hypothesized that EPI is a settlement and metamorphosis inducer for Manila clam. EPI may lead to larvae settlement and metamorphosis by binding to the receptors on the membrane and then changing the gene expression of larvae cells.

  4. Sequence analysis of 18S rRNA gene of six Veneridae clams (Mollusca: Bivalvia)%6种帘蛤科贝类18S rRNA基因全序列比较分析

    Institute of Scientific and Technical Information of China (English)

    程汉良; 彭永兴; 王芳; 孟学平; 阎斌伦; 董志国

    2008-01-01

    对文蛤(Meretrix meretrix)、青蛤(Cyclina sinensis)、江户布目蛤(Protothaca jedoensis)、薄片镜蛤(Dosinia corrugata)、紫石房蛤(Saxidomus purpuraus)和菲律宾蛤仔(Ruditapes philippinarum)6种帘蛤科(Veneridae)贝类的18S rRNA基因序列进行了PCR扩增并测序,以期获得这一序列的基本特征,评估其种间变异程度,探讨这一序列在种类鉴定和分子系统发育等研究中的应用价值.测序结果表明,文蛤、青蛤、江户布目蛤、薄片镜蛤、紫石房蛤和菲律宾蛤仔18S rRNA基因序列全长分别为1 900bp、1 838bp、1 831 bp、1 831 bp、1 829bp和1 833bp.序列中A、T、C和G碱基的平均含量分别为24.0%、24.0%、24.2%和27.8%.用MEGA软件对6种帘蛤18S rRNA基因全序列进行了分析,对位排列后的总长度1 906bp,其中变异位点210个,简约信息位点28个,si/sv=1.4(46/32).从GenBank下载了7种帘蛤科贝类18S rDNA全序列,与本研究实测的6种帘蛤一起用MegAlign软件对其18S rDNA序列进行了比对,物种间序列相似百分比为88.7%~99.7%.文蛤与其他12物种间序列差异较大,序列差异百分比均超过了10%,其他各物种间序列差异百分比不超过3%.以异韧带亚纲(Anomalodesmata)笋螂目(Pholadomyoida)的Lyonsia floridana和Cardiomya costellata为外群,采用相邻连接法(NJ)和最大简约法(MP)构建了帘蛤科贝类的系统发育树,其拓扑结构显示雪蛤亚科(Chioninae)、帘蛤亚科(Venerinae)和镜蛤亚科(Dosiniinae)的种类首先聚在一起,形成一个聚类簇;缀锦蛤亚科(Tapetinae)、卵蛤亚科(Pitarinae)、仙女蛤亚科(Callistinae)、青蛤亚科(Cyelininae)和文蛤亚科(Meretricinae)的种类先后分别单独聚成一枝;最后所有帘蛤科物种聚为一枝,与外群相区别,说明18S rDNA序列适合作为帘蛤科系统发育研究的分子标记.

  5. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic). Softshell Clam.

    Science.gov (United States)

    1986-08-01

    was achieved in 40 days. to the substrate to become a juvenile Shaw (1965) also reported a spring clam. A byssus (sticky thread) is spawning failure...for locomotion (Green 1975). Although The fertilized egg takes about usually attached to the substrate by 12 h to develop into the planktonic the byssus ...clams per square foot; it is highest at depths of 3-4 Eventually the byssus is shed and m, temperatures less than 28 °C and the adult lifestyle

  6. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic). SURF CLAM

    Science.gov (United States)

    1983-10-01

    invisible, outer, jellylike layer and mine surf clam gender (Ropes et al. the germinal vesicle (Ropes 1980). 1969). Male and female surf clams Longo...Jacobsen, M. K., and W. E. Old, Jr. Lindley, M. G., and R. S. Shallen- 1966. On the identity of Spisula berger. 1976, Purification and similis. Am...1966. A quantitative Masse, H. 1975. Feeding biotogy of .3-year-survey on the meiofauna Astropecten aranciacus. Cah , of known macrofauna communities

  7. Length-weight relationship of the freshwater clam, Galatea paradoxa (born 1778) from the Volta Estuary, Ghana.

    Science.gov (United States)

    Obirikorang, K A; Adjei-Boateng, D; Madkour, H A; Amisah, S; Otchere, F A

    2013-02-15

    The length-weight relationship of the threatened freshwater clam, Galatea paradoxa (Born 1778) from the Volta Estuary, Ghana was studied over a two-year period, from March 2008 to February 2010, to aid in the development of stock assessment models for the sustainable management of the remaining clam stock. Data reported in this study were collected at monthly intervals and covered varying depths of the Estuary ranging from 0.5 to about 10 m. Overall, a total of 5276 clams with shell lengths ranging from 3.40 to 89.24 mm and total weight from 0.10 to 154.00 g were sampled during the study period. The length-weight relationships were highly significant (p < 0.0001) for all the months and the b-values ranged from 2.023 (January 2010) to 3.874 (June 2009). The calculated b-values indicated that clams exhibited different growth patterns at different periods but overall, the pooled samples of 5276 individuals exhibited an isometric growth pattern (b = 3.003). The observed monthly growth patterns exhibited by G. paradoxa appeared to be largely influenced by the reproductive cycle of the organism. During the periods leading to spawning, the clams generally exhibited positive allometric growth patterns (weight increasing faster than length) which appeared to be strongly linked to the build-up of proteins and carbohydrates in their tissues. Successive negative allometric growth patterns (length increasing faster relative to weight) were, however, observed from March to June 2008 and from December 2009 to February 2010, which are possibly indicative of the loss in tissue weight that occurs as a direct result of the spawning process. It will thus be suitable to institute a close season to coincide with the spawning period of the clams to avoid the harvesting of clams during the spawning period which will enhance future recruitment of the clam stock.

  8. Long-Term Acclimation to Different Thermal Regimes Affects Molecular Responses to Heat Stress in a Freshwater Clam Corbicula Fluminea

    Science.gov (United States)

    Falfushynska, Halina I.; Phan, Tuan; Sokolova, Inna M.

    2016-12-01

    Global climate change (GCC) can negatively affect freshwater ecosystems. However, the degree to which freshwater populations can acclimate to long-term warming and the underlying molecular mechanisms are not yet fully understood. We used the cooling water discharge (CWD) area of a power plant as a model for long-term warming. Survival and molecular stress responses (expression of molecular chaperones, antioxidants, bioenergetic and protein synthesis biomarkers) to experimental warming (20–41 °C, +1.5 °C per day) were assessed in invasive clams Corbicula fluminea from two pristine populations and a CWD population. CWD clams had considerably higher (by ~8–12 °C) lethal temperature thresholds than clams from the pristine areas. High thermal tolerance of CWD clams was associated with overexpression of heat shock proteins HSP70, HSP90 and HSP60 and activation of protein synthesis at 38 °C. Heat shock response was prioritized over the oxidative stress response resulting in accumulation of oxidative lesions and ubiquitinated proteins during heat stress in CWD clams. Future studies should determine whether the increase in thermal tolerance in CWD clams are due to genetic adaptation and/or phenotypic plasticity. Overall, our findings indicate that C. fluminea has potential to survive and increase its invasive range during warming such as expected during GCC.

  9. Effects of clam size, food type, sediment characteristic, and seawater carbonate chemistry on grazing capacity of Venus clam Cyclina sinensis (Gmelin, 1791)

    Science.gov (United States)

    Lin, Tingting; Zhou, Kai; Liu, Xin; Lai, Qifang; Zhang, Dong; Shi, Liyan

    2016-10-01

    Aquaculture in saline-alkaline water has a major problem: microalgal blooming causes the pH of water to increase dramatically, thereby causing damage to the reared organisms. To solve this problem, we set out to find a candidate filter-feeding bivalve species suitable for saline-alkaline water to graze on microalgae and to control the pH. In the current study, we investigated the effect of carbonate alkalinity (CA, 2.5, 10.0, and 20.0 meq/L) and pH (8.0, 8.5, and 9.0) on the grazing capacity (GC) of the clam Cyclina sinensis. Additionally, the effect of clam size (small, medium, and large) and microalgae species (Nannochloropsis oculata, Chaetoceros müelleri, and Isochrysis galbana), and the effect of bottom sediment characteristic (mud, sandy mud, and muddy sand) and thickness (3 and 6 cm) were analyzed as well. The results show that the GC on I. galbana was the highest and small size had the maximum GC/W (W: wet weight including body and shells). No significant differences were observed between sediment type and thickness. Regarding CA and pH, a significant decrease in GC by the pH or by their interaction was found. The GC of C. sinensis was not greatly reduced in the treatments of pH≤8.5 and CA≤20.0, and also not affected by bottom sediment type, indicating that this clam is capable to manage microalgal concentrations and might be a candidate species for pH reduction in saline-alkaline water ponds.

  10. Creep deformation and rupture behavior of CLAM steel at 823 K and 873 K

    Science.gov (United States)

    Zhong, Boyu; Huang, Bo; Li, Chunjing; Liu, Shaojun; Xu, Gang; Zhao, Yanyun; Huang, Qunying

    2014-12-01

    China Low Activation Martensitic (CLAM) steel is selected as the candidate structural material in Fusion Design Study (FDS) series fusion reactor conceptual designs. The creep property of CLAM steel has been studied in this paper. Creep tests have been carried out at 823 K and 873 K over a stress range of 150-230 MPa. The creep curves showed three creep regimes, primary creep, steady-state creep and tertiary creep. The relationship between minimum creep rate (ε˙min) and the applied stress (σ) could be described by Norton power law, and the stress exponent n was decreased with the increase of the creep temperature. The creep mechanism was analyzed with the fractographes of the rupture specimens which were examined by scanning electron microscopy (SEM). The coarsening of precipitates observed with transmission electron microscope (TEM) indicated the microstructural degradation after creep test.

  11. Optimization of hard clams, polychaetes, physical disturbance and denitrifying bacteria of removing nutrients in marine sediment.

    Science.gov (United States)

    Shen, Hui; Thrush, Simon F; Wan, Xihe; Li, Hui; Qiao, Yi; Jiang, Ge; Sun, Ruijian; Wang, LiBao; He, Peimin

    2016-09-15

    Marine organisms are known to play important roles in transforming nutrients in sediments, however, guidelines to optimize sediment restoration are not available. We conducted a laboratory mesocosm experiment to investigate the role of hard clams, polychaetes, the degree of physical disturbance and denitrifying bacterial concentrations in removing total nitrogen (TN), total phosphorus (TP), and total organic carbon (TOC) in marine sediments. Response surface methodology was employed to analyze the results of initial experiments and in a subsequent experiment identified optimal combinations of parameters. Balancing the TN, TP, TOC removal efficiency, our model predicted 39% TN removal, 33% TP removal, and 42% TOC removal for a 14-day laboratory bioremediation trial using hard clams biomass of 1.2kgm(-2), physical disturbance depth of 16.4cm, bacterial density of 0.18Lm(-2), and polychaetes biomass of 0.16kgm(-2), respectively. These results emphasize the value of combining different species in field-based bioremediation.

  12. Heavy Metals Backgrounds in Sediments From the Sacca di Goro (NE, Italy

    Directory of Open Access Journals (Sweden)

    Claudio Natali

    2016-08-01

    Full Text Available A textural and geochemical characterization of sediments from the Sacca di Goro lagoon floor has been performed in order to evaluate the present day granulometric distribution and the geochemical budget with respect to literature values. 10 samples have been collected along a WE transect crosscutting the whole Sacca di Goro lagoon in order to explore the maximum lithological variability and to identify geochemical trends. Results show that the present day superficial sediment are coarser in grain size with respect to those studied in the past, in turn implying lower concentrations of Potentially Toxic Elements (PTE. PTE enrichments miming those observed 20 years ago are recorded only locally, in connection with parallel increase of fine fraction and organic matter. Traces of Cu, V and Pb have been also found in the shells of farmed Manila clam (Ruditapes Philippinarum collected within the sediment samples, suggesting PTE bioavailability and accumulation. The comparison of the results with literature data highlights that PTE contents of the Sacca di Goro lagoon deserve more frequent and systematic monitoring both for the high hydrodynamicity of this environment and for the high anthropogenic impact. The analysis of metals in Manila clam shells has a twofold purpose because it represents a further biomarker of the ecosystem, and also provide a geochemical fingerprint of the local shellfish production that could help the traceability in the market, and discrimination from shellfish produced in other area that are not properly controlled from the sanitary point of view.

  13. DoE optimization of a mercury isotope ratio determination method for environmental studies.

    Science.gov (United States)

    Berni, Alex; Baschieri, Carlo; Covelli, Stefano; Emili, Andrea; Marchetti, Andrea; Manzini, Daniela; Berto, Daniela; Rampazzo, Federico

    2016-05-15

    By using the experimental design (DoE) technique, we optimized an analytical method for the determination of mercury isotope ratios by means of cold-vapor multicollector ICP-MS (CV-MC-ICP-MS) to provide absolute Hg isotopic ratio measurements with a suitable internal precision. By running 32 experiments, the influence of mercury and thallium internal standard concentrations, total measuring time and sample flow rate was evaluated. Method was optimized varying Hg concentration between 2 and 20 ng g(-1). The model finds out some correlations within the parameters affect the measurements precision and predicts suitable sample measurement precisions for Hg concentrations from 5 ng g(-1) Hg upwards. The method was successfully applied to samples of Manila clams (Ruditapes philippinarum) coming from the Marano and Grado lagoon (NE Italy), a coastal environment affected by long term mercury contamination mainly due to mining activity. Results show different extents of both mass dependent fractionation (MDF) and mass independent fractionation (MIF) phenomena in clams according to their size and sampling sites in the lagoon. The method is fit for determinations on real samples, allowing for the use of Hg isotopic ratios to study mercury biogeochemical cycles in complex ecosystems.

  14. Blood clams community (Anadara granoasa in The Eastern Coastal Waters of Banyuasin Regency South Sumatera

    Directory of Open Access Journals (Sweden)

    Rini Setianingsih

    2016-04-01

    Full Text Available Abstract: This research aimed to study existence of blood clams population and the environmental factors that affect them. This research was conducted in the coastal waters of Banyuasin in February 2015. The blood clamp sample was collected using Ekman Grab at low tide. From the observation in the research site, the highest population density was 60 ind/m2 with clay substrate texture, while the lowest density was 20 ind/m2 on the dusty clay substrate. Blood clams population was not found on the sand substrate texture station. Morphometric data showed that the blood clam population in the research site, including the medium category with b < 3 growth pattern (allometric negative. The results of PCA analysis proved that the habitat texture and sediment organic habitats were dominant factors besides the chemical physics environmental factors of the waters (temperature, salinity, pH. Keywords: Blood clams, density, morphometric, PCA Abstrak (Indonesian: Penelitian ini bertujuan untuk mempelajari keberadaan populasi kerang-darah dan faktor lingkungan yang mempengaruhinya. Penelitian ini dilakukan di perairan pesisir Banyuasin pada bulan Februari 2015. Sampel kerang-darah diambil dengan mengunakan Ekman Grab pada saat air surut. Dari hasil pengamatan pada lokasi penelitian, kepadatan populasi kerang-darah tertinggi adalah 60 ind/m2 dengan tekstur substrat lempung, sedangkan kepadatan terendah adalah 20 ind/m2 pada substrat lempung berdebu. Populasi kerang-darah tidak ditemukan pada stasiun dengan tekstur substrat pasir. Data morfometrik menunjukan bahwa populasi kerang-darah di lokasi penelitian termasuk kategori sedang dengan pola pertumbuhan b < 3 (allometrik negatif. Hasil analisis PCA membuktikan bahwa tekstur habitat dan bahan organik sedimen merupakan faktor dominan disamping faktor lingkungan fisika kimia perairan (suhu, salinitas, pH. Kata kunci: Kerang-darah, kepadatan, morfometrik, PCA

  15. Composting clam processing wastes in a laboratory- and pilot-scale in-vessel system.

    Science.gov (United States)

    Hu, Zhenhu; Lane, Robert; Wen, Zhiyou

    2009-01-01

    Waste materials from the clam processing industry (offal, shells) have several special characteristics such as a high salinity level, a high nitrogen content, and a low C/N ratio. The traditional disposal of clam waste through landfilling is facing the challenges of limited land available, increasing tipping fees, and strict environmental and regulatory scrutiny. The aim of this work is to investigate the performance of in-vessel composting as an alternative for landfill application of these materials. Experiments were performed in both laboratory-scale (5L) and pilot-scale (120L) reactors, with woodchips as the bulking agent. In the laboratory-scale composting test, the clam waste and woodchips were mixed in ratios from 1:0.5 to 1:3 (w/w, wet weight). The high ratios resulted in a better temperature performance, a higher electrical conductivity, and a higher ash content than the low-ratio composting. The C/N ratio of the composts was in the range of 9:1-18:1. In the pilot-scale composting test, a 1:1 ratio of clam waste to woodchips was used. The temperature profile during the composting process met the US Environmental Protection Agency sanitary requirement. The final cured compost had a C/N ratio of 14.6, with an ash content of 167.0+/-14.1g/kg dry matter. In addition to the major nutrients (carbon, nitrogen, calcium, magnesium, phosphorus, potassium, sulfur, and sodium), the compost also contained trace amounts of zinc, manganese, copper, and boron, indicating that the material can be used as a good resource for plant nutrients.

  16. Gametogenic development and spawning of the mud clam, Polymesoda erosa (Solander, 1876) at Chorao Island, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Clemente, S.; Ingole, B.S.

    species. The dominant plants are Rhizophora sp., Avicennia sp. Sonneratia sp. and Excoecaria sp. Reproductive cycle Size of the clams was not restricted for a standard size and specimens representing all the size classes were analysed. Size classes were... using Statistica version 5.1 software. ANOVA was applied to test for differences in egg diameter and egg number between sampling dates and among different size classes. Significance was concluded at pB0.05. To ensure assumptions for normality...

  17. Multi-species generalist predation on the stochastic harvested clam Tivela mactroides (Mollusca, Bivalvia)

    Science.gov (United States)

    Turra, Alexander; Fernandez, Wellington S.; Bessa, Eduardo; Santos, Flavia B.; Denadai, Márcia R.

    2015-12-01

    Top-down control is an important force modulating the abundance of prey and structuring marine communities. The harvested trigonal clam Tivela mactroides is hypothesized to be part of the diet of a variety of marine organisms, with its stock influencing predator abundance and being influenced by them. Here we analyzed the diet of potential predators of T. mactroides in Caraguatatuba Bay, northern coast of São Paulo State, Brazil, to identify the main consumers of this marine resource, and also to address the importance of this clam in the diet of each predator. Samples were taken year-round by trawls; all specimens collected were identified and measured and the food items identified and quantified. Twenty-one species consumed T. mactroides, whose importance in the diet varied greatly in both the volume ingested and the frequency of occurrence (pompano Trachinotus carolinus > blue crab Callinectes danae > starfish Astropecten marginatus). Top-down influence on T. mactroides was also dependent on the abundance of consumers (yellow catfish Cathorops spixii > rake stardrum Stellifer rastrifer > barred grunt Conodon nobilis > A. marginatus). Considering the mean volume ingested, the frequency of occurrence of T. mactroides in the diet, and the relative abundance of consumers, the predators that most influenced T. mactroides were T. carolinus, A. marginatus, and C. danae, in decreasing order. Large numbers of small-sized individuals of T. mactroides (<10 mm) were generally preyed upon by A. marginatus, which may have a stronger effect on clam abundance in comparison to C. danae and T. carolinus, which preyed upon larger clams. In conclusion, the results of this study indicate that predators' consumption of T. mactroides in Caraguatatuba Bay can influence its stocks, mainly due to the type and/or abundance of predator species, the volume and number of individuals of T. mactroides preyed upon, and the temporal variations in the abundance of predators.

  18. Effects of stocking density on intermediate culture of the razor clam Ensis arcuatus (Pharidae: Bivalvia)

    OpenAIRE

    Da Costa Gonzalez, Fiz; Barreiro, Berta; Ojea, Justa; Novoa, Susana; Martinez-patino, Dorotea

    2015-01-01

    Commercial production of most bivalve species involves a phase of intermediate cultivation during which juveniles are grown under protected conditions until they can be transferred to the final grow-out location. Consequently, the aim of this study was investigating the effect of density on growth and survival in the intermediate culture of the razor clam Ensis arcuatus in raft. Two series of experiments were performed, using in the first experiment two holding systems: 5-L plastic bottles an...

  19. Changes in fatty acid composition in the giant clam Tridacna maxima in response to thermal stress

    Directory of Open Access Journals (Sweden)

    Vaimiti Dubousquet

    2016-10-01

    Full Text Available Temperature can modify membrane fluidity and thus affects cellular functions and physiological activities. This study examines lipid remodelling in the marine symbiotic organism, Tridacna maxima, during a time series of induced thermal stress, with an emphasis on the morphology of their symbiont Symbiodinium. First, we show that the French Polynesian giant clams harbour an important proportion of saturated fatty acids (SFA, which reflects their tropical location. Second, in contrast to most marine organisms, the total lipid content in giant clams remained constant under stress, though some changes in their composition were shown. Third, the stress-induced changes in fatty acid (FA diversity were accompanied by an upregulation of genes involved in lipids and ROS pathways. Finally, our microscopic analysis revealed that for the giant clam's symbiont, Symbiodinium, thermal stress led to two sequential cell death processes. Our data suggests that the degradation of Symbiodinium cells could provide an additional source of energy to T. maxima in response to heat stress.

  20. Interaction of CLAM Steel with Plasma in HT-7 Tokamak During High Parameter Operation

    Institute of Scientific and Technical Information of China (English)

    LI Chunjing; HUANG Qunying; FENG Yan; LI Jiangang; KONG Mingguang

    2007-01-01

    A Plasma Surface Interaction(PSI)experiment on China Low Activation Martensitic(CLAM)steel was done to check if CLAM steel could be used as a Plasma Facing Material (PFM).A specimen with a diameter of 45 mm was exposed to 897 shots of deuterium plasmas with a total duration of 712 sec at a minor radius of 30 cm in HT-7 tokamak.During the exposure experiment,no observable influence Was found on plasma performance.After exposure,the surface of the specimen seemed as smooth as before but with some colour change at the margin of the specimen.Even though some micro-damage,such as dense blisters,melting,splashing,depositions,and dust,Was found on local surfaces with Scanning Electron Microscopic(SEM)observation.The reflectivity of the specimen decreased only slightly.All of these shows CLAM steel has good stability and irradiation resistance.With further optimization,it could possibly be used as the first mirror material for plasma diagnostics in tokamaks.

  1. Modeling habitat suitability of the invasive clam Corbicula fluminea in a Neotropical shallow lagoon, southern Brazil

    Directory of Open Access Journals (Sweden)

    T. C. L. Silveira

    Full Text Available Abstract This study aimed to model the habitat suitability for an invasive clam Corbicula fluminea in a coastal shallow lagoon in the southern Neotropical region (–30.22, –50.55. The lagoon (19km2, maximum deep 2.5m was sampled with an Ekman dredge in an orthogonal matrix comprising 84 points. At each sampling point, were obtained environmental descriptors as depth, organic matter content (OMC, average granulometry (Avgran, and the percentage of sand (Pcsand. Prediction performance of Generalized Linear Models (GLM, Generalized Additive Models (GAM and Boosted Regression Tree (BRT were compared. Also, niche overlapping with other native clam species (Castalia martensi, Neocorbicula limosa and Anodontites trapesialis was examined. A BRT model with 1400 trees was selected as the best model, with cross-validated correlation of 0.82. The relative contributions of predictors were Pcsand-42.6%, OMC-35.8%, Avgran-10.9% and Depth-10.8%. Were identified that C. fluminea occur mainly in sandy sediments with few organic matter, in shallow areas nor by the shore. The PCA showed a wide niche overlap with the native clam species C. martensi, N. limosa and A. trapesialis.

  2. Enzyme responses and lipid peroxidation in gills and hepatopancreas of clam Mactra vereformis, following cadmium exposure

    Institute of Scientific and Technical Information of China (English)

    WANG Xiaoyu; YANG Hongsheng; LIU Guangbin; WANG Qing

    2011-01-01

    To assess the toxicity of heavy metal pollution to marine intertidal shellfish,enzymatic responses and lipid peroxidation were investigated in the clam Mactra vereformis exposed to cadmium under laboratory conditions.Three antioxidant enzymes (superoxide dismutase,SOD; catalase,CAT;glutathione peroxidase,GPx),two immune defense enzymes (acid phosphatase,ACP; alkaline phosphatase,ALP),and one lipid peroxidation product (malondialdehyde,MDA) were measured in the gills and the hepatopancreas of the clam exposed to 0,25,75,and 125 μg/L cadmium for 0,1,3,5,and 7 d.The results show that the concentrations of antioxidant enzymes in the organs soared to a peak value on the first day and then decreased afterwards in most cases.CAT and GPx activities in the hepatopancreas were higher than in the gills,but the SOD activity was lower in the bepatopancreas.ACP activity was unchanged until Day 3 in the hepatopancreas and until Day 5 in gills,when it began to increase.ALP activity showed no significant relationship with Cd treatment.MDA concentrations increased in the two tissues after Cd exposure,peaked on Day 3 in gills,and on Day 5 in hepatopancreas.These observations show that changes in the activities of antioxidant enzymes and ACP reflect the time course of oxidative stress in the clam caused by Cd,and could be used as potential biomarkers for ecotoxicological bioassays of heavy metals.

  3. Changes in fatty acid composition in the giant clam Tridacna maxima in response to thermal stress

    Science.gov (United States)

    Dubousquet, Vaimiti; Gros, Emmanuelle; Berteaux-Lecellier, Véronique; Viguier, Bruno; Raharivelomanana, Phila; Bertrand, Cédric; Lecellier, Gaël J.

    2016-01-01

    ABSTRACT Temperature can modify membrane fluidity and thus affects cellular functions and physiological activities. This study examines lipid remodelling in the marine symbiotic organism, Tridacna maxima, during a time series of induced thermal stress, with an emphasis on the morphology of their symbiont Symbiodinium. First, we show that the French Polynesian giant clams harbour an important proportion of saturated fatty acids (SFA), which reflects their tropical location. Second, in contrast to most marine organisms, the total lipid content in giant clams remained constant under stress, though some changes in their composition were shown. Third, the stress-induced changes in fatty acid (FA) diversity were accompanied by an upregulation of genes involved in lipids and ROS pathways. Finally, our microscopic analysis revealed that for the giant clam's symbiont, Symbiodinium, thermal stress led to two sequential cell death processes. Our data suggests that the degradation of Symbiodinium cells could provide an additional source of energy to T. maxima in response to heat stress. PMID:27543058

  4. Giant Clams and Rising CO2: Light May Ameliorate Effects of Ocean Acidification on a Solar-Powered Animal.

    Science.gov (United States)

    Watson, Sue-Ann

    2015-01-01

    Global climate change and ocean acidification pose a serious threat to marine life. Marine invertebrates are particularly susceptible to ocean acidification, especially highly calcareous taxa such as molluscs, echinoderms and corals. The largest of all bivalve molluscs, giant clams, are already threatened by a variety of local pressures, including overharvesting, and are in decline worldwide. Several giant clam species are listed as 'Vulnerable' on the IUCN Red List of Threatened Species and now climate change and ocean acidification pose an additional threat to their conservation. Unlike most other molluscs, giant clams are 'solar-powered' animals containing photosynthetic algal symbionts suggesting that light could influence the effects of ocean acidification on these vulnerable animals. In this study, juvenile fluted giant clams Tridacna squamosa were exposed to three levels of carbon dioxide (CO2) (control ~400, mid ~650 and high ~950 μatm) and light (photosynthetically active radiation 35, 65 and 304 μmol photons m-2 s-1). Elevated CO2 projected for the end of this century (~650 and ~950 μatm) reduced giant clam survival and growth at mid-light levels. However, effects of CO2 on survival were absent at high-light, with 100% survival across all CO2 levels. Effects of CO2 on growth of surviving clams were lessened, but not removed, at high-light levels. Shell growth and total animal mass gain were still reduced at high-CO2. This study demonstrates the potential for light to alleviate effects of ocean acidification on survival and growth in a threatened calcareous marine invertebrate. Managing water quality (e.g. turbidity and sedimentation) in coastal areas to maintain water clarity may help ameliorate some negative effects of ocean acidification on giant clams and potentially other solar-powered calcifiers, such as hard corals.

  5. Giant Clams and Rising CO2: Light May Ameliorate Effects of Ocean Acidification on a Solar-Powered Animal.

    Directory of Open Access Journals (Sweden)

    Sue-Ann Watson

    Full Text Available Global climate change and ocean acidification pose a serious threat to marine life. Marine invertebrates are particularly susceptible to ocean acidification, especially highly calcareous taxa such as molluscs, echinoderms and corals. The largest of all bivalve molluscs, giant clams, are already threatened by a variety of local pressures, including overharvesting, and are in decline worldwide. Several giant clam species are listed as 'Vulnerable' on the IUCN Red List of Threatened Species and now climate change and ocean acidification pose an additional threat to their conservation. Unlike most other molluscs, giant clams are 'solar-powered' animals containing photosynthetic algal symbionts suggesting that light could influence the effects of ocean acidification on these vulnerable animals. In this study, juvenile fluted giant clams Tridacna squamosa were exposed to three levels of carbon dioxide (CO2 (control ~400, mid ~650 and high ~950 μatm and light (photosynthetically active radiation 35, 65 and 304 μmol photons m-2 s-1. Elevated CO2 projected for the end of this century (~650 and ~950 μatm reduced giant clam survival and growth at mid-light levels. However, effects of CO2 on survival were absent at high-light, with 100% survival across all CO2 levels. Effects of CO2 on growth of surviving clams were lessened, but not removed, at high-light levels. Shell growth and total animal mass gain were still reduced at high-CO2. This study demonstrates the potential for light to alleviate effects of ocean acidification on survival and growth in a threatened calcareous marine invertebrate. Managing water quality (e.g. turbidity and sedimentation in coastal areas to maintain water clarity may help ameliorate some negative effects of ocean acidification on giant clams and potentially other solar-powered calcifiers, such as hard corals.

  6. Measuring the economic value of alternative clam fishing management practices in the Venice Lagoon: results from a conjoint valuation application

    Science.gov (United States)

    Nunes, Paulo A. L. D.; Rossetto, Luca; de Blaeij, Arianne

    2004-11-01

    This article focuses on the economic valuation of alternative clam management practices in the Venice Lagoon. The proposed valuation method is characterized by the design of a survey questionnaire applied to the fishermen population. In each questionnaire, two fishing alternatives are described. The respondent is asked to choose one of them. This valuation method, referred in the article as conjoint valuation, gives sufficient flexibility to set, alter, and combine the valuation of different clam management practices. Furthermore, this approach presents an important advantage to the well-known contingent valuation method since it makes the monetary valuation of each management attribute possible. Estimation results show that all three attributes used in the questionnaire to describe and value different clam management practices—price of the annual permit and fishing technological system—are statistically robust, indicating that fishermen bear a utility change whenever these attributes change. In particular, fishermen's willingness to pay for a larger clam fishing area ranges between 568 and 811 € per year. In addition, an individual's willingness to pay for a fishing practice exclusively based on the vibrant rake system ranges between 1005 and 2456 €. Finally, the adoption of a clam fish management practice in the Venice Lagoon that is exclusively based on the use of manual rakes, which is associated with the lowest damage to the lagoon ecosystem, will represent a welfare loss of 5904 € per fisherman per year. Combining such a value estimate with the total number of fishermen currently operating in the Lagoon of Venice, the welfare loss associated with the adoption of this type of clam management policy amounts to 11.8 € million per year. This figure can be regarded as an upper bound to the cost of implementation of a clam fishing system anchored in the use of manual, ecosystem friendly rakes.

  7. Genetic considerations for mollusc production in aquaculture: current state of knowledge.

    Directory of Open Access Journals (Sweden)

    Marcela eAstorga

    2014-12-01

    Full Text Available IIn 2012, world mollusk production in aquaculture reached a volume of 15,171,000 tons, representing 23% of total aquaculture production and positioning mollusks as the second most important category of aquaculture products (fishes are the first. Clams and oysters are the mollusk species with the highest production levels, followed in descending order by mussels, scallops and abalones. In view of the increasing importance attached to genetic information on aquaculture, which can help with good maintenance and thus the sustainability of production, the present work offers a review of the state of knowledge on genetic and genomic information about mollusks produced in aquaculture. The analysis was applied to mollusks which are of importance for aquaculture, with emphasis on the 5 species with the highest production levels. According to FAO, these are: Japanese clam Ruditapes philippinarum; Pacific oyster Crassostrea gigas; Chilean mussel Mytilus chilensis; Blood clam Anadara granosa and Chinese clam Sinonovacula constricta. To date, the genomes of 5 species of mollusks have been sequenced, only one of which, Crassostrea gigas, coincides with the species with the greatest production in aquaculture. Another important species whose genome has been sequenced is Mytilus galloprovincialis, which is the second most important mussel in aquaculture production, after M. chilensis. Few genetic improvement programs have been reported in comparison with the number reported in fish species. The most commonly investigated species are oysters, with at least 5 genetic improvement programs reported, followed by abalones with 2 programs and mussels with one. The results of this work will establish the current situation with respect to the genetics of mollusks which are of importance for aquaculture production, in order to assist future decisions to ensure the sustainability of these resources.

  8. Purification and Characterization of Hemagglutinating Proteins from Poker-Chip Venus (Meretrix lusoria and Corbicula Clam (Corbicula fluminea

    Directory of Open Access Journals (Sweden)

    Chin-Fu Cheng

    2012-01-01

    Full Text Available Hemagglutinating proteins (HAPs were purified from Poker-chip Venus (Meretrix lusoria and Corbicula clam (Corbicula fluminea using gel-filtration chromatography on a Sephacryl S-300 column. The molecular weights of the HAPs obtained from Poker-chip Venus and Corbicula clam were 358 kDa and 380 kDa, respectively. Purified HAP from Poker-chip Venus yielded two subunits with molecular weights of 26 kDa and 29 kDa. However, only one HAP subunit was purified from Corbicula clam, and its molecular weight was 32 kDa. The two Poker-chip Venus HAPs possessed hemagglutinating ability (HAA for erythrocytes of some vertebrate animal species, especially tilapia. Moreover, HAA of the HAP purified from Poker-chip Venus was higher than that of the HAP of Corbicula clam. Furthermore, Poker-chip Venus HAPs possessed better HAA at a pH higher than 7.0. When the temperature was at 4°C–10°C or the salinity was less than 0.5‰, the two Poker-chip Venus HAPs possessed better HAA compared with that of Corbicula clam.

  9. Filtration and respiration rates of the short-necked clam Paphia undulata (Born, 1778 (Mollusca, Pelecypoda: Veneridae under laboratory conditions

    Directory of Open Access Journals (Sweden)

    Laureen Morillo Manalo

    2010-12-01

    Full Text Available The filtration and respiration rates of various size classes (35-39.99, 40-44.99,45-49.99, 50-54.99 and 55-59.99 mm of the short-necked clam Paphia undulata were measured in the laboratory. The effects of three light regimes (0 lux, 172.22 lux and 645.83 lux, three microalgal species (Isochrysis galbana, Tetraselmis tetrahele and Chaetoceros calcitrans and four microalgal concentrations (10, 25, 50 and 100 x 104 cells ml-1 on filtration rates were investigated. Mean filtration rate was highest (0.57 ± 0.04 Lh-1ind.-1 under total darkness. This can be attributed to the natural environment of this species which is characterized by silty substrate and low visibility. Filtration was also highest in the microalga Isochrysis galbana (0.67 ± 0.05. Rates initially increased from low to moderate microalgal concentrations (25 x 104 cells ml-1 and decreased at higher concentrations. Filtration generally decreased with increase in clam size. Light intensity, microalgal species and microalgal concentration showed significant effects on filtration. Respiration of fed clams was higher (0.138 ± 0.026 ml O2h-1ind.-1 than unfed clams (0.053± 0.025 ml O2h-1 nd.-1 and increased with clam size.

  10. Bioaccumulation of polychlorinated biphenyls and metals from contaminated sediment by freshwater prawns, Macrobrachium rosenbergii and clams, Corbicula fluminea

    Energy Technology Data Exchange (ETDEWEB)

    Tatem, H.E.

    1986-02-01

    Freshwater prawns, Macrobrachium rosenbergii, and clams, Corbicula Fluminea, were exposed for 48 or 50 days to three concentrations of a river sediment that contained environmental contaminants such as polychlorinated biphenyls (PCBs) and metals. The PCB sediment bioaccumulation factors (BAF) for prawns ranged from 0.11 to 0.90 for 1242 and 0.20 to 2.40 for 1254, and were highest for animals exposed to 10% sediment. Exposed clams also accumulated PCBs (1242 + 1254) from the sediment. Sediment BAFs for clams were 0.54 to 12.52 and were highest for animals exposed to 10% sediment. Analyses of clams for metals showed lead (Pb) in exposed animals at higher concentrations compared with controls. Bioaccumulation of Pb differed from PCB in that the Pb concentrations did not increase over time and concentrations were higher among animals exposed to 10% sediment compared to animals exposed to 100% sediment. Sediment 11-80 contained 99 mg/kg of Pb while exposed animals, at 48 days, contained approximately 2.2 mg/kg Pb. Analysis of clams for cadmium (Cd) showed exposed animals contained less Cd than controls.

  11. Effect of post-weld heat treatment on the mechanical properties of CLAM/316L dissimilar joint

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Junyu [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); University of Science and Technology of China, Hefei, Anhui 230027 (China); Huang, Bo [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Wu, Qingsheng, E-mail: qingsheng.wu@fds.org.cn [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Li, Chunjing; Huang, Qunying [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

    2015-11-15

    Highlights: • Dissimilar joints between CLAM and 316L steels welded by TIG were investigated. • After PWHTs, the hardening in HAZ on the CLAM steel side decreased remarkably. • Tempering at 740 °C for 2 h was considered as the preferable treatment rule. - Abstract: Dissimilar welding between China low activation martensitic (CLAM) steel and 316L austenitic stainless steel was investigated to achieve the reliable connection between test blanket modules (TBMs) and piping system in the international thermonuclear experimental reactor (ITER). The dissimilar joints were welded by tungsten inert gas (TIG) welding process with a filler material type-309. In order to stabilize the microstructure and improve the strength and toughness, post-weld heat treatments (PWHTs) of tempering at 740 °C, 780 °C and 820 °C, respectively, for 2 h were performed. The microstructure observation showed that tempering at 740 °C for 2 h was the preferable PWHT rule in this work. After the treatment, the hardening in heat affected zone (HAZ) on the CLAM steel side decreased remarkably. The tensile strength of the joint was roughly the same as that of the base metal. The impact toughness of HAZ on the CLAM steel side was 77% of that of the base metal. The absorbed energy of HAZ of 316L steel decreased by 93 J, and that of weld metal (WM) was 110 J after the treatment.

  12. Updated mitochondrial phylogeny of Pteriomorph and Heterodont Bivalvia, including deep-sea chemosymbiotic Bathymodiolus mussels, vesicomyid clams and the thyasirid clam Conchocele cf. bisecta.

    Science.gov (United States)

    Ozawa, Genki; Shimamura, Shigeru; Takaki, Yoshihiro; Yokobori, Shin-Ichi; Ohara, Yasuhiko; Takishita, Kiyotaka; Maruyama, Tadashi; Fujikura, Katsunori; Yoshida, Takao

    2017-02-01

    The mitochondrial genomes of bivalves have often been used for comparative genomics and for resolving phylogenetic relationships. More than 100 bivalve complete mitochondrial genomes have been sequenced to date. However, few mitochondrial genomes have been reported for deep-sea chemosymbiotic bivalves, which belong to the subclasses Pteriomorphia and Heterodonta. In the present study, we sequenced the mitochondrial genomes of eight deep-sea chemosymbiotic bivalve species: three species of Bathymodiolus mussels (B. japonicus, B. platifrons, and B. septemdierum), four species of vesicomyid clams (Abyssogena mariana, A. phaseoliformis, Isorropodon fossajaponicum, and Phreagena okutanii, all of which were formerly classified in the genus Calyptogena), and one species of thyasirid clam (Conchocele cf. bisecta). With a few exceptions, these mitochondrial genomes contained genes that are typical of metazoans: 13 protein-coding genes, two rRNA genes, and 22 tRNA genes. The major non-coding region with a high A+T content of each genome, which contained tandem repeats and hairpins, was hypothesized to function as a control region. The phylogenetic trees of Pteriomorphia and Heterodonta were reconstructed based on the concatenated sequences of 14 shared genes. Bathymodiolus formed a monophyletic clade with asymbiotic Mytilidae mussels, the vesicomyid clams formed a monophyly that was sister to the Veneridae, and C. cf. bisecta branched basally in the Heterodonta. It is known that the gene orders of mitochondrial genomes vary among bivalves. To examine whether gene order variation exhibits phylogenetic signals, tree topologies based on the minimum number of gene rearrangements were reconstructed for two clades (superfamily Tellinoidea, which includes the Psammobiidae, Semelidae, Solecurtidae, and Tellinidae; and the clade comprising the Myidae, Mactridae, Arcticidae, Vesicomyidae, and Veneridae) with high statistical support in sequence-based phylogenies. The resulting tree

  13. Evaluation of Using Caged Clams to Monitor Contaminated Groundwater Exposure in the Near-Shore Environment of the Hanford Site 300 Area

    Energy Technology Data Exchange (ETDEWEB)

    Larson, Kyle B.; Poston, Ted M.; Tiller, Brett L.

    2008-01-31

    The Asiatic clam (Corbicula fluminea) has been identified as an indicator species for locating and monitoring contaminated groundwater in the Columbia River. Pacific Northwest National Laboratory conducted a field study to explore the use of caged Asiatic clams to monitor contaminated groundwater upwelling in the 300 Area near-shore environment and assess seasonal differences in uranium uptake in relation to seasonal flow regimes of the Columbia River. Additional objectives included examining the potential effects of uranium accumulation on growth, survival, and tissue condition of the clams. This report documents the field conditions and procedures, laboratory procedures, and statistical analyses used in collecting samples and processing the data. Detailed results are presented and illustrated, followed by a discussion comparing uranium concentrations in Asiatic clams collected at the 300 Area and describing the relationship between river discharge, groundwater indicators, and uranium in clams. Growth and survival, histology, and other sources of environmental variation also are discussed.

  14. Verification of the effect of surface preparation on Hot Isostatic Pressing diffusion bonding joints of CLAM steel

    Science.gov (United States)

    Zhao, Yanyun; Li, Chunjing; Huang, Bo; Liu, Shaojun; Huang, Qunying

    2014-12-01

    Hot Isostatic Pressing (HIP) diffusion bonding with CLAM steel is the primary candidate fabrication technique for the first wall (FW) of DFLL-TBM. Surface state is one of the key factors for the joints quality. The effect of surface state prepared with grinder and miller on HIP diffusion bonding joints of CLAM steel was investigated. HIP diffusion bonding was performed at 140 MPa and 1373 K within 3 h. The mechanical properties of the joints were investigated with instrumented Charpy V-notch impact tests and the microstructures of the joints were analyzed with scanning electron microscopy (SEM). The results showed that the milled samples with fine surface roughness were more suitable for CLAM steel HIP diffusion bonding.

  15. Verification of the effect of surface preparation on Hot Isostatic Pressing diffusion bonding joints of CLAM steel

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yanyun [University of Science and Technology of China, Hefei, Anhui 230027 (China); Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Li, Chunjing, E-mail: chunjing.li@fds.org.cn [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Huang, Bo; Liu, Shaojun [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Huang, Qunying [University of Science and Technology of China, Hefei, Anhui 230027 (China); Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

    2014-12-15

    Hot Isostatic Pressing (HIP) diffusion bonding with CLAM steel is the primary candidate fabrication technique for the first wall (FW) of DFLL-TBM. Surface state is one of the key factors for the joints quality. The effect of surface state prepared with grinder and miller on HIP diffusion bonding joints of CLAM steel was investigated. HIP diffusion bonding was performed at 140 MPa and 1373 K within 3 h. The mechanical properties of the joints were investigated with instrumented Charpy V-notch impact tests and the microstructures of the joints were analyzed with scanning electron microscopy (SEM). The results showed that the milled samples with fine surface roughness were more suitable for CLAM steel HIP diffusion bonding.

  16. Molecular cloning and differential expression patterns of sigma and omega glutathione S-transferases from Venerupis philippinarum to heavy metals and benzo[a]pyrene exposure

    Science.gov (United States)

    Zhang, Linbao; Wu, Huifeng; Liu, Xiaoli; Chen, Leilei; Wang, Qing; Zhao, Jianmin; You, Liping

    2012-05-01

    Glutathione S-transferases (GSTs) are a class of enzymes that facilitate the detoxification of xenobiotics, and also play important roles in antioxidant defense. We identified two glutathione S-transferase isoforms (VpGSTS, sigma GST; VpGSTO, omega GST) from Venerupis philippinarum by RACE approaches. The open reading frames of VpGSTS and VpGSTO were of 612 bp and 729 bp, encoding 203 and 242 amino acids with an estimated molecular mass of 22.88 and 27.94 kDa, respectively. The expression profiles of VpGSTS and VpGSTO responded to heavy metals and benzo[a]pyrene (B[a]P) exposure were investigated by quantitative real-time RT-PCR. The expression of VpGSTS and VpGSTO were both rapidly up-regulated, however, they showed differential expression patterns to different toxicants. Cd displayed stronger induction of VpGSTS expression with an approximately 12-fold increase than that of VpGSTO with a maximum 6.4-fold rise. Cu exposure resulted in similar expression patterns for both VpGSTS and VpGSTO. For B[a]P exposure, the maximum induction of VpGSTO was approximately two times higher than that of VpGSTS. Altogether, these findings implied the involvement of VpGSTS and VpGSTO in host antioxidant responses, and highlighted their potential as a biomarker to Cd and B[a]P exposure.

  17. Between a rock and a soft place: Using optical ages to date ancient clam gardens on the Pacific Northwest

    Science.gov (United States)

    Neudorf, Christina M.; Smith, Nicole; Lepofsky, Dana; Toniello, Ginevra; Lian, Olav B.

    2017-01-01

    Rock-walled archaeological features are notoriously hard to date, largely because of the absence of suitable organic material for radiocarbon dating. This study demonstrates the efficacy of dating clam garden wall construction using optical dating, and uses optical ages to determine how sedimentation rates in the intertidal zone are affected by clam garden construction. Clam gardens are rock-walled, intertidal terraces that were constructed and maintained by coastal First Nation peoples to increase bivalve habitat and productivity. These features are evidence of ancient shellfish mariculture on the Pacific Northwest and, based on radiocarbon dating, date to at least the late Holocene. Optical dating exploits the luminescence signals of quartz or feldspar minerals to determine the last time the minerals were exposed to sunlight (i.e., their burial age), and thus does not require the presence of organic material. Optical ages were obtained from three clam garden sites on northern Quadra Island, British Columbia, and their reliability was assessed by comparing them to radiocarbon ages derived from shells underneath the clam garden walls, as well as below the terrace sediments. Our optical and radiocarbon ages suggest that construction of these clam garden walls commenced between ~1000 and ~1700 years ago, and our optical ages suggest that construction of the walls was likely incremental and increased sedimentation rates in the intertidal zone by up to fourfold. Results of this study show that when site characteristics are not amenable to radiocarbon dating, optical dating may be the only viable geochronometer. Furthermore, dating rock-walled marine management features and their geomorphic impact can lead to significant advances in our understanding of the intimate relationships that Indigenous peoples worldwide developed with their seascapes. PMID:28182645

  18. Frequency, Magnitude, and Possible Causes of Stranding and Mass-Mortality Events of the Beach Clam Tivela mactroides (Bivalvia: Veneridae).

    Science.gov (United States)

    Turra, Alexander; Pombo, Maíra; Petracco, Marcelo; Siegle, Eduardo; Fonseca, Mariana; Denadai, Márcia R

    2016-01-01

    Stranding combined with mass-mortality events of sandy-beach organisms is a frequent but little-understood phenomenon, which is generally studied based on discrete episodes. The frequency, magnitude, and possible causes of stranding and mass-mortality events of the trigonal clam Tivela mactroides were assessed based on censuses of stranded individuals, every four days from September 2007 through December 2008, in Caraguatatuba Bay, southeastern Brazil. Stranded clams were classified as dying (closed valves did not open when forced) or dead (closed valves were easily opened). Information on wave parameters and the living intertidal clam population was used to assess possible causes of stranding. This fine-scale monitoring showed that stranding occurred widely along the shore and year-round, with peaks interspersed with periods of low or no mortality. Dead clams showed higher mean density than dying individuals, but a lower mean shell length, attributed to a higher tolerance to desiccation of larger individuals. Wave height had a significant negative relationship to the density of dying individuals, presumed to be due to the accretive nature of low-energy waves: when digging out, clams would be more prone to be carried upward and unable to return; while larger waves, breaking farther from the beach and with a stronger backwash, would prevent stranding in the uppermost areas. This ecological finding highlights the need for refined temporal studies on mortality events, in order to understand them more clearly. Last, the similar size structure of stranded clams and the living population indicated that the stranded individuals are from the intertidal or shallow subtidal zone, and reinforces the ecological and behavioral components of this process, which have important ecological and socioeconomic implications for the management of this population.

  19. Between a rock and a soft place: Using optical ages to date ancient clam gardens on the Pacific Northwest.

    Science.gov (United States)

    Neudorf, Christina M; Smith, Nicole; Lepofsky, Dana; Toniello, Ginevra; Lian, Olav B

    2017-01-01

    Rock-walled archaeological features are notoriously hard to date, largely because of the absence of suitable organic material for radiocarbon dating. This study demonstrates the efficacy of dating clam garden wall construction using optical dating, and uses optical ages to determine how sedimentation rates in the intertidal zone are affected by clam garden construction. Clam gardens are rock-walled, intertidal terraces that were constructed and maintained by coastal First Nation peoples to increase bivalve habitat and productivity. These features are evidence of ancient shellfish mariculture on the Pacific Northwest and, based on radiocarbon dating, date to at least the late Holocene. Optical dating exploits the luminescence signals of quartz or feldspar minerals to determine the last time the minerals were exposed to sunlight (i.e., their burial age), and thus does not require the presence of organic material. Optical ages were obtained from three clam garden sites on northern Quadra Island, British Columbia, and their reliability was assessed by comparing them to radiocarbon ages derived from shells underneath the clam garden walls, as well as below the terrace sediments. Our optical and radiocarbon ages suggest that construction of these clam garden walls commenced between ~1000 and ~1700 years ago, and our optical ages suggest that construction of the walls was likely incremental and increased sedimentation rates in the intertidal zone by up to fourfold. Results of this study show that when site characteristics are not amenable to radiocarbon dating, optical dating may be the only viable geochronometer. Furthermore, dating rock-walled marine management features and their geomorphic impact can lead to significant advances in our understanding of the intimate relationships that Indigenous peoples worldwide developed with their seascapes.

  20. Frequency, Magnitude, and Possible Causes of Stranding and Mass-Mortality Events of the Beach Clam Tivela mactroides (Bivalvia: Veneridae)

    Science.gov (United States)

    Turra, Alexander; Pombo, Maíra; Petracco, Marcelo; Siegle, Eduardo; Fonseca, Mariana; Denadai, Márcia R.

    2016-01-01

    Stranding combined with mass-mortality events of sandy-beach organisms is a frequent but little-understood phenomenon, which is generally studied based on discrete episodes. The frequency, magnitude, and possible causes of stranding and mass-mortality events of the trigonal clam Tivela mactroides were assessed based on censuses of stranded individuals, every four days from September 2007 through December 2008, in Caraguatatuba Bay, southeastern Brazil. Stranded clams were classified as dying (closed valves did not open when forced) or dead (closed valves were easily opened). Information on wave parameters and the living intertidal clam population was used to assess possible causes of stranding. This fine-scale monitoring showed that stranding occurred widely along the shore and year-round, with peaks interspersed with periods of low or no mortality. Dead clams showed higher mean density than dying individuals, but a lower mean shell length, attributed to a higher tolerance to desiccation of larger individuals. Wave height had a significant negative relationship to the density of dying individuals, presumed to be due to the accretive nature of low-energy waves: when digging out, clams would be more prone to be carried upward and unable to return; while larger waves, breaking farther from the beach and with a stronger backwash, would prevent stranding in the uppermost areas. This ecological finding highlights the need for refined temporal studies on mortality events, in order to understand them more clearly. Last, the similar size structure of stranded clams and the living population indicated that the stranded individuals are from the intertidal or shallow subtidal zone, and reinforces the ecological and behavioral components of this process, which have important ecological and socioeconomic implications for the management of this population. PMID:26745804

  1. Comparison of selenium bioaccumulation in the clams Corbicula fluminea and Potamocorbula amurensis: A bioenergetic modeling approach

    Science.gov (United States)

    Lee, B.-G.; Lee, J.-S.; Luoma, S.N.

    2006-01-01

    Selenium uptake from food (assimilation efficiency) and dissolved phase (influx rate) as well as loss kinetics (efflux rate) were compared between two bivalves, Corbicula fluminea and Potamocorbula amurensis. The effects of salinity and temperature on these kinetic parameters for both clam species also were evaluated. The Asiatic clam, C. fluminea, more efficiently assimilated Se associated with algae (66-87%) than Se associated with oxic sediments (20-37%). However, no consistent difference was found between Se assimilation efficiencies from both food types (19-60%) for P. amurensis. The temperature and salinity had a minor influence on the Se assimilation from ingested food. However, the effects of temperature and salinity were more evident in the uptake from dissolved sources. The influx rate of Se(IV) increased by threefold with the increase of temperature from 5 to 21??C for C. fluminea. The increase of salinity from 4 to 20 psu decreased the uptake rate constant (ku) of Se in P. amurensis from 0.011 to 0.005 L/g/h, whereas salinity change (0-8 psu) had a negligible effect on the Se influx rate of C. fluminea. The Se influx rate of P. amurensis decreased by half with the 3.5-fold increase in tissue dry weight. The rate constant of loss was greater for P. amurensis (0.029/d at 8 psu) than for C. fluminea (0.014/d at 0 psu and 0.01/d at 8 psu). A bioenergetic model suggests that dietary uptake is the dominant pathway for Se bioaccumulation in the two clams in San Francisco Bay and that interspecies differences in Se bioaccumulation can be explained by differences in food ingestion rates. ?? 2006 SETAC.

  2. Evaluation of Norfolk Harbor Deepening Project (A Study on Its Possible Impact on Oysters, Hard Clams and Oyster Drills).

    Science.gov (United States)

    1984-06-20

    Virginia 23062 DTIC 20 June 1984 ELECTE ~L&JMAR 12 i9BB IA B! ,", Contract No. DACW65-84-M-0056 -Ap’oved to: publicO t01b0 I D)WtbuZidon Unlimited .~Norfolk...impact on the transport of the larval oysters and hard clams during their planktonic stage. Oysters and hard clams are widely tolerant to high salinity...planktonic for about 2 weeks and during this period are transported by currents. This latter aspect will be covered later in our discussion on oysters. ~i

  3. Environmental salinity modulates the effects of elevated CO2 levels on juvenile hard-shell clams, Mercenaria mercenaria.

    Science.gov (United States)

    Dickinson, Gary H; Matoo, Omera B; Tourek, Robert T; Sokolova, Inna M; Beniash, Elia

    2013-07-15

    Ocean acidification due to increasing atmospheric CO2 concentrations results in a decrease in seawater pH and shifts in the carbonate chemistry that can negatively affect marine organisms. Marine bivalves such as the hard-shell clam, Mercenaria mercenaria, serve as ecosystem engineers in estuaries and coastal zones of the western Atlantic and, as for many marine calcifiers, are sensitive to the impacts of ocean acidification. In estuaries, the effects of ocean acidification can be exacerbated by low buffering capacity of brackish waters, acidic inputs from freshwaters and land, and/or the negative effects of salinity on the physiology of organisms. We determined the interactive effects of 21 weeks of exposure to different levels of CO2 (~395, 800 and 1500 μatm corresponding to pH of 8.2, 8.1 and 7.7, respectively) and salinity (32 versus 16) on biomineralization, shell properties and energy metabolism of juvenile hard-shell clams. Low salinity had profound effects on survival, energy metabolism and biomineralization of hard-shell clams and modulated their responses to elevated PCO2. Negative effects of low salinity in juvenile clams were mostly due to the strongly elevated basal energy demand, indicating energy deficiency, that led to reduced growth, elevated mortality and impaired shell maintenance (evidenced by the extensive damage to the periostracum). The effects of elevated PCO2 on physiology and biomineralization of hard-shell clams were more complex. Elevated PCO2 (~800-1500 μatm) had no significant effects on standard metabolic rates (indicative of the basal energy demand), but affected growth and shell mechanical properties in juvenile clams. Moderate hypercapnia (~800 μatm PCO2) increased shell and tissue growth and reduced mortality of juvenile clams in high salinity exposures; however, these effects were abolished under the low salinity conditions or at high PCO2 (~1500 μatm). Mechanical properties of the shell (measured as microhardness and

  4. Paralytic shellfish poisoning toxins accumulation in purple clam Hiatula rostrata and toxic effect on milkfish Chanos chanos larval fish.

    Science.gov (United States)

    Chen, C Y

    2001-11-01

    In an attempt to feed purple clams (Hiatula rostrata) with dinoglagellate Alexandrium minutum, the maximal accumulation toxicity of paralytic shellfish poisoning (PSP) toxins reached 40.6 MU/g on day 5 of feeding. Subsequently, the toxicity increased no further, although purple clams ingested more toxic algae. Furthermore, when milkfish (Chanos chanos) larvae were treated with toxic, nontoxic A. minutum or PSP toxin-containing extract in the water medium, it was found that the mortality of fish increased with the increasing concentrations of toxic algae. PSP toxin-containing extract did not show any toxic effect on milkfish larvae.

  5. Expression of cyp1a protein in the freshwater clam Corbicula fluminea (Müller

    Directory of Open Access Journals (Sweden)

    Vranković Jelena

    2011-01-01

    Full Text Available We investigated the expression of CYP1A in the foot, gill and visceral mass of the freshwater clam Corbicula fluminea in relation to polychlorinated biphenyls (PCBs exposure. Different PCBs congeners were found in the foot and visceral mass, while the expression of CYP1A was observed only in the visceral mass. However the level of CYP1A expression in the visceral mass was not related to the level of PCBs present in the tissue. Our results indicate a higher rate of biotransformation and lower threshold of CYP1A induction in the visceral mass compared with other tissues.

  6. In situ evaluation of wastewater discharges and the bioavailability of contaminants to marine biota

    Energy Technology Data Exchange (ETDEWEB)

    Maranho, L.A., E-mail: lmaranho@gmail.com [Andalusian Centre of Marine Science and Technology (CACYTMAR), University of Cádiz, Polygon Río San Pedro, s/n, 11510 Puerto Real, Cádiz (Spain); Physical Chemical Department, Faculty of Marine and Environmental Sciences, University of Cádiz, Polygon Río San Pedro, s/n, 11510 Puerto Real, Cádiz (Spain); André, C. [Emerging Methods, Aquatic Contaminants Research Division, Environment Canada, 105 McGill Street, 7th floor, H2Y 2E7 Montreal, Quebec (Canada); DelValls, T.A. [Physical Chemical Department, Faculty of Marine and Environmental Sciences, University of Cádiz, Polygon Río San Pedro, s/n, 11510 Puerto Real, Cádiz (Spain); Gagné, F. [Emerging Methods, Aquatic Contaminants Research Division, Environment Canada, 105 McGill Street, 7th floor, H2Y 2E7 Montreal, Quebec (Canada); Martín-Díaz, M.L. [Andalusian Centre of Marine Science and Technology (CACYTMAR), University of Cádiz, Polygon Río San Pedro, s/n, 11510 Puerto Real, Cádiz (Spain); Physical Chemical Department, Faculty of Marine and Environmental Sciences, University of Cádiz, Polygon Río San Pedro, s/n, 11510 Puerto Real, Cádiz (Spain)

    2015-12-15

    Marine sediment quality of wastewater discharges areas was determined by using in situ caged clams Ruditapes philippinarum taking into account the seasonality. Clams were caged in sediment directly affected by wastewater discharges at four sites (P1, P2, P3, P4) at the Bay of Cádiz (SW, Spain), and one reference site (P6). Exposure to contaminated sediments was confirmed by measurement of metals and As, PAH, pharmaceutical products and surfactants (SAS) in bottom sediments. Biological effects were determined by following biomarkers of exposure (activities of 7-ethoxyresorufin O-deethylase — EROD, dibenzylfluorescein dealkylase — DBF, glutathione S-transferase — GST, glutathione peroxidase — GPX, glutathione reductase — GR and acetylcholinesterase — AChE), effects (lysosomal membrane stability — LMS, DNA damage and lipid peroxidation — LPO), energy status (total lipids — TLP and mitochondrial electron transport — MET), and involved in the mode of action of pharmaceutical products (monoamine oxidase activity — MAO, alkali-labile phosphates — ALP levels and cyclooxygenase activity — COX). In winter, urban effluents were detoxified by phase I biotransformation (CYP3A-like activity), phase II (GST), and the activation of antioxidant defence enzymes (GR). Urban effluents lead to the detoxification metabolism (CYP1A-like), oxidative effects (LPO and DNA damage), neurotoxicity (AChE) and neuroendocrine disruption (COX and ALP levels) involved in inflammation (P1 and P2) and changes in reproduction as spawning delay (P3 and P4) in clams exposed in summer. Adverse effects on biota exposed to sediment directly affected by wastewater discharges depend on the chemical contamination level and also on the reproductive cycle according to seasonality. - Highlights: • Sediment quality of wastewater discharges evaluated by caged clams R. philippinarum • Exposure was confirmed by measurement of metal and organic compounds in sediments. • Winter

  7. Studies on molluscan glycosaminoglycans (GAG) from backwater clam Donax cuneatus (Linnaeus)

    Institute of Scientific and Technical Information of China (English)

    P Vijayabaskar; ST Somasundaram

    2012-01-01

    Objective: To investigate the potent and specific anticoagulant activity of molluscan glycosaminoglycans (GAGs) isolated from whole clam tissue Donax cuneatus (D. cuneatus). Methods: Purification of few milligram quantities of GAGs from this tissue sample permitted a thorough examination of its anticoagulant activity characterization, which was partially purified by fractionation by anion exchange chromatography using DEAE cellulose column. The isolated crude and partially purified fractionated sample was showing metachromatic shift while using azure-A. The sample also exhibited prominent of biological and anti-fXa anticoagulant activity assays. Mobility was analyzed by two different buffer systems using agarose gel electrophoresis.Results:The fractionated molluscan GAG was also found to have similar peaks as that of standard heparin when assessed by the FT-IR spectrum. Finally molecular weight was determined by the gradient PAGE for crude and fractionated-II GAG, which were found to be 65 000 Da and 50 000 Da, respectively. Conclusions: The bivalve GAG was subjected to fractionation for further purification and its chemical components were analyzed. The fractionated clam heparin also showed substantial in vitro anticoagulant activity than that of commercial heparins.

  8. A light-dependent ammonia-assimilating mechanism in the ctenidia of a giant clam

    Science.gov (United States)

    Hiong, Kum C.; Choo, Celine Y. L.; Boo, Mel V.; Ching, Biyun; Wong, Wai P.; Chew, Shit F.; Ip, Yuen K.

    2017-03-01

    Giant clams harbor symbiotic zooxanthellae and manifest light-enhanced calcification. In light, they also increase the absorption and assimilation of exogenous ammonia, but the roles of the host and symbionts are unclear and the reason for light dependency remains enigmatic. Here, we report the complete coding cDNA sequence of a glutamine synthetase (GS), from the ctenidia (gill) of Tridacna squamosa. The deduced GS amino acid sequence was closely related to other animal GSs, indicating a host origin. The GS/GS transcript level and protein abundance increased significantly in the ctenidia after 12 h of light exposure. These results denote the ctenidia as the site of light-enhanced ammonia absorption with the absorbed ammonia being assimilated to glutamine by the host GS. Immunofluorescence microscopy confirmed that GS was expressed predominantly in the cytoplasm of the epithelial cells separating the tertiary water channels from the hemolymph inside the ctenidia. Hence, unlike symbiotic cnidarians, the host clam probably supplies exogenous nitrogen as glutamine from the ctenidia, through the hemolymph and tubular fluid, to the nitrogen-deficient zooxanthellae which reside extracellularly in the extensible outer mantle. This is the first report on light-dependent gene and protein expression of a host enzyme involved in nitrogen metabolism in an alga-invertebrate association.

  9. Real-Time Mesoscale Forecast Support During the CLAMS Field Campaign

    Institute of Scientific and Technical Information of China (English)

    WANG Donghai; P. MINNIS; T. P. CHARLOCK; D. K. ZHOU; F. G. ROSE; W. L. SMITH; W. L. SMITH Jr.; L. NGUYEN

    2007-01-01

    This paper reports the use of a specialized, mesoscale, numerical weather prediction (NWP) system and a satellite imaging and prediction system that were set up to support the CLAMS (Chesapeake Lighthouse and Aircraft Measurements for Satellites) field campaign during the summer of 2001. The primary objective of CLAMS was to validate satellite-based retrievals of aerosol properties and vertical profiles of the radiative flux, temperature and water vapor. Six research aircraft were deployed to make detailed coincident measurements of the atmosphere and ocean surface with the research satellites that orbited overhead. The mesoscale weather modeling system runs in real-time to provide high spatial and temporal resolution for forecasts that are delivered via the World Wide Web along with a variety of satellite imagery and satellite location predictions. This system is a multi-purpose modeling system capable of both data analysis/assimilation and multi-scale NWP ranging from cloud-scale to larger than regional scale. This is a three-dimensional, nonhydrostatic compressible model in a terrain-following coordinate. The model employs advanced numerical techniques and contains detailed interactive physical processes. The utility of the forecasting system is illustrated throughout the discussion on the impact of the surface-wind forecast on BRDF (Bidirectional Reflectance Distribution Function) and the description of the cloud/moisture forecast versus the aircraft measurement.

  10. Fishery of the short-necked clam Paphia undulata in Southern Negros Occidental, Central Philippines

    Directory of Open Access Journals (Sweden)

    Karen A. Villarta

    2010-06-01

    Full Text Available This study documents the fishery of the short-necked clam Paphia undulata in coastal waters of southern Negros Occidental. Catch and effort estimates were determined based on daily records of compressor divers gathered between February-July 2008 in Himamaylan City and July 2008-May 2009 in the town of Hinigaran. Fishing and marketing practices in both areas were also documented and population biology information noted.Compared to earlier conditions, present fishing patterns show a worsened stage of overexploitation primarily characterized by collection of predominantly small and immature (mostly <45 mm shell lengths sizes. Intensity/duration and location of fishing also varied due to both abundance and demand factors.The difference in sizes of clams and the varying fishing durations in each area suggest a non-uniform pattern of settlement resulting most likely from differential larval recruitment, the likely factors causing the local boom and bust fishery. The larger and long term extent of the effect of these factors can only be further investigated by parallel 2-3 year fishery-dependent and -independent surveys

  11. Overview on the welding technologies of CLAM steel and the DFLL TBM fabrication

    Directory of Open Access Journals (Sweden)

    Junyu Zhang

    2016-12-01

    Full Text Available Dual Functional Lithium Lead (DFLL blanket was proposed for its advantages of high energy exchange efficiency and on-line tritium extraction, and it was selected as the candidate test blanket module (TBM for China Fusion Engineering Test Reactor (CFETR and the blanket for Fusion Design Study (FDS series fusion reactors. Considering the influence of high energy fusion neutron irradiation and high heat flux thermal load on the blanket, China Low Activation Martensitic (CLAM steel was selected as the structural material for DFLL blanket. The structure of the blanket and the cooling internal components were pretty complicated. Meanwhile, high precision and reliability were required in the blanket fabrication. Therefore, several welding techniques, such as hot isostatic pressing diffusion bonding, tungsten inner gas welding, electron beam welding and laser beam welding were developed for the fabrication of cooling internals and the assembly of the blanket. In this work, the weldability on CLAM steel by different welding methods and the properties of as-welded and post-weld heat-treated joints were investigated. Meanwhile, the welding schemes and the assembly strategy for TBM fabrication were raised. Many tests and research efforts on scheme feasibility, process standardization, component qualification and blanket assembly were reviewed.

  12. Use of ELISA for the detection and typing of three HBGAs in shellfish%贝类中3种组织血型抗原ELISA检测方法的建立与分型

    Institute of Scientific and Technical Information of China (English)

    刘帅帅; 姚琳; 马丽萍; 周德庆; 赵峰

    2013-01-01

      人类组织血型抗原(histo-blood group antigens, HBGAs)是诺如病毒(NoVs)的结合受体,本研究假设贝类中也存在类似的HBGAs并且特异性地富集NoVs,利用HBGAs单克隆抗体,建立贝类中3种HBGAs的ELISA检测方法,分析牡蛎(Crassostrea gigas)、缢蛏(Sinonovacula constricta)、菲律宾蛤仔(Ruditapes philippinarum)、紫贻贝(Mytilus galloprovincialis)、毛蚶(Scapharca subcrenata)、栉孔扇贝(Chlamys farreri)等6种双壳贝类中HBGAs的类型.结果显示,在上述6种贝类中都检测出 A型抗原,其中菲律宾蛤仔的检出率为11.6%(9/77),紫贻贝的检出率为28.1%(16/57),缢蛏样品为72.3%(47/65),栉孔扇贝为84.6%(58/69),其余贝类检出率为100%;只有牡蛎样品检出 H 抗原,检出率为30.7%(28/91);在缢蛏和毛蚶样品中检测出 B 型抗原,检出率分别为76.9%(50/65)和77.8(56/72).结果表明贝类中存在不止1种类型的HBGAs.%The histo-blood group antigens (HBGAs) located on cells of the human gastrointestinal tract function as receptors for NoVs. It is hypothesized that HBGA-like receptors are present in shellfish and are responsible for the specific accumulation of NoVs. We used human HBGA-specific monoclonal antibodies (MAbs) to develop an ELISA method for detection of three forms of HBGA in six bivalve shellfish species (oysters, razor clam, clam, blue mussel, blood clam, and scallop). All six species expressed type-A HBGAs. The detection rate of type-A HBGAs was 11.6%, 28.1%, 72.3%, and 84.6% in Ruditapes philippinarum, Mytilus galloprovincialis, Si-nonovacula constricta, and Chlamys farreri tissue, respectively. All samples of oyster and blood clam contained type-A HBGAs. Type-H HBGAs were found only in oysters with a detection rate of 30.7%. Type-B HBGAs were present in the razor clam and blood clam (detection rate of 76.9% and 77.8%, respectively). Our results suggest that multiple HBGAs are expressed in bivalve shellfish and provide insight into the mechanism

  13. Selective pressurized liquid extraction technique capable of analyzing dioxins, furans, and PCBs in clams and crab tissue.

    Science.gov (United States)

    Subedi, Bikram; Aguilar, Lissette; Williams, E Spencer; Brooks, Bryan W; Usenko, Sascha

    2014-04-01

    A selective pressurized liquid extraction technique (SPLE) was developed for the analysis of polychlorodibenzo-p-dioxins, polychlorodibenzofurans (PCDD/Fs) and dioxin-like polychlorobiphenyls (dl-PCBs) in clam and crab tissue. The SPLE incorporated multiple cleanup adsorbents (alumina, florisil, silica gel, celite, and carbopack) within the extraction cell. Tissue extracts were analyzed by high resolution gas chromatography coupled with electron capture negative ionization mass spectrometry. Mean recovery (n = 3) and percent relative standard deviation for PCDD/Fs and dl-PCBs in clam and crabs was 89 ± 2.3 and 85 ± 4.0, respectively. The SPLE method was applied to clams and crabs collected from the San Jacinto River Waste Pits, a Superfund site in Houston, TX. The dl-PCBs concentrations in clams and crabs ranged from 50 to 2,450 and 5 to 800 ng/g ww, respectively. Sample preparation time and solvents were reduced by 92 % and 65 %, respectively, as compared to USEPA method 1613.

  14. The involvement of cysteine-rich intestinal protein in early development and innate immunity of Asiatic hard clam, Meretrix meretrix.

    Science.gov (United States)

    Chen, Hongjian; Yang, Xue; Tang, Ting; Li, Juan; Liu, Baozhong; Liu, Fengsong; Xie, Song

    2014-10-01

    Cysteine-rich intestinal protein (CRIP), a Zn(2+)-binding protein, contains a single copy of the highly conserved double-zinc-finger structure known as the LIM (lin-11-isl-1-mec-3) motif. In this paper, a cDNA encoding MmCRIP was isolated from the Asiatic hard clam Meretrix meretrix. The full-length cDNA of MmCRIP consists of a 237-bp open reading frame that encodes a polypeptide of 78 amino acids with a predicted molecular weight (MW) of 8635.8 Da and theoretical isoelectric point (pI) of 9.01. Bioinformatics analysis showed that it belonged to a new member of the CRIP subfamily. Relationship analysis revealed that MmCRIP has high-levels of sequence similarity to many CRIPs reported in other animals, particularly in invertebrates. Real-time PCR analysis showed that the highest level of MmCRIP expression was in hemocyte tissue and at pediveligers stage. To investigate immune function, mature clams were challenged with Aeromonas hydrophila. During A. hydrophila infection, up-regulation of MmCRIP transcript in clam's hemocyte, gill and hepatopancreas was detected. DsRNAi (double-strand RNA interference) approach was employed to study the function of MmCRIP and the data showed that inactivation of the MmCRIP gene blocked larvae development and caused mass mortalities. The probable roles of MmCRIP in clam early development and innate immunity are presented for the first time.

  15. Sodium Gill Potential as a Tool to Monitor Valve Closure Behavior in Freshwater Clam Corbicula fluminea in Response to Copper

    Directory of Open Access Journals (Sweden)

    Wei-Yu Chen

    2008-09-01

    Full Text Available Valve closure behavior in freshwater clam Corbicula fluminea is a biologically sensitive endpoint. The purpose of this paper was to derive an electrophysiological response model of C. fluminea to assess copper (Cu-sodium (Na interactions in gill membrane, whereby valve closure behavior and Cu toxicity could be monitored. The proposed model was based on the integration of Cu bioavailability, Na and Cu internalizations, and electrochemically-based gill potentials. Based on Na active transport under non-equilibrium conditions, predicted gill potential of -8.2 mV agreed reasonably well with published the measured transepithelial potential of -7 mV in C. fluminea. Our proposed framework captured the general features observed in model applications including: (i 50% inhibitory Cu2+ activities for Na membrane potential (ENa and uptake rate (JNa were estimated to be 0.072 and 0.043 mM, respectively, with a stoichiometry of 3Cu2+: 1ENa and 1JNa; (ii the external Cu2+-dependent internal Na concentration could be parsimoniously estimated, and (iii the site-specific clam gill potentials could be monitored. Here we provided a new approach to monitor waterborne metal toxicity to reduce the nationwide economic losses due to bans on harvesting of contaminated clam and the potential risks to the health of clams.

  16. Rangia and Marsh Clams, Rangia cuneata, R. flexuosa, and Polymesoda caroliniana, in Eastern México: Distribution, Biology and Ecology, and Historical Fisheries

    OpenAIRE

    Wakida-Kusunoki, Armando T.; MacKenzie, Jr., Clyde L.

    2004-01-01

    Rangia and marsh clams, Rangia cuneata, R. flexuosa, and Polymesoda caroliniana, occur in brackish waters along México’s eastern coast from the northern State of Tamaulipas to the southern State of Campeche. The clams were important to the prehispanic people in the southern part of the State of Veracruz, where they were used as food and as construction material. In modern times, they are harvested for food. The fishermen wade in shallow water and harvest the clams in soft sediments by hand...

  17. Molecular cloning and differential expression patterns of sigma and omega glutathione S-transferases from Venerupis philippinarum to heavy metals and benzo[a]pyrene exposure

    Institute of Scientific and Technical Information of China (English)

    ZHANG Linbao; WU Huifeng; LIU Xiaoli; CHEN Leilei; WANG Qing; ZHAO Jianmin; YOU Liping

    2012-01-01

    Glutathione S-transferases (GSTs) are a class of enzymes that facilitate the detoxification of xenobiotics,and also play important roles in antioxidant defense.We identified two glutathione S-transferase isoforms (VpGSTS,sigma GST; VpGSTO,omega GST) from Venerupis philippinarum by RACE approaches.The open reading frames of VpGSTS and VpGSTO were of 612 bp and 729 bp,encoding 203 and 242 amino acids with an estimated molecular mass of 22.88 and 27.94 kDa,respectively.The expression profiles of VpGSTS and VpGSTO responded to heavy metals and benzo[a]pyrene (B[a]P) cxposure were investigated by quantitative real-time RT-PCR.The expression of VpGSTS and VpGSTO were both rapidly up-regulated,however,they showed differential expression patterns to different toxicants.Cd displayed stronger induction of VpGSTS expression with an approximately 12-fold increase than that of VpGSTO with a maximum 6.4-fold rise.Cu exposure resulted in similar expression patterns for both VpGSTS and VpGSTO For B[a]P exposure,the maximum induction of VpGSTO was approximately two times higher than that of VpGSTS.Altogether,these findings implied the involvement of VpGSTS and VpGSTO in host antioxidant responses,and highlighted their potential as a biomarker to Cd and B[a]P exposure.

  18. Quantitative determination of gymnodimine-A by high performance liquid chromatography in contaminated clams from Tunisia coastline.

    Science.gov (United States)

    Marrouchi, Riadh; Dziri, Faten; Belayouni, Nawel; Hamza, Asma; Benoit, Evelyne; Molgó, Jordi; Kharrat, Riadh

    2010-10-01

    Quantitative determination by high performance liquid chromatography (HPLC) was performed for gymnodimine-A (GYM-A), a phycotoxin responsible for the contamination of Tunisian clams. This study demonstrates a rapid and reproducible HPLC-ultraviolet (UV) method for extraction, detection and quantification of GYM-A in toxic clams. The extraction of GYM-A from the digestive gland of clams in acetone, subsequent clean-up with diethyl ether and extraction with dichloromethane is the more valid protocol. Chromatography analyses were performed using a gradient of acetonitrile-water (10:90 to 90:10), containing trifluoroacetic acid (0.1%) for 20 min at 1 mL/min rate with a C18 column. Recovery rates exceeded 96%, and limits of detection and quantification were 5 ng/mL and 8 ng/g digestive gland, respectively. Repeatability and reproducibility were tested for various samples containing different levels of GYM-A. A significant correlation was observed between toxicity level of samples and the determined amount of GYM-A. Also, the persistence of GYM-A in contaminated clams from Boughrara lagoon was demonstrated. The kinetics discharge study of GYM-A in controlled medium, during 1 month, showed that the process of depuration was biphasic with an exponential discharge of 75% of the total amount of sequestered GYM-A during the first 12 days followed by a slow discharge (>10%) for the subsequent days up to the seventeenth day. This is the first time that a quantitative study of GYM-A in clams from Tunisian coasts is performed through the development of a new method for detection and quantify of this phycotoxin. We found HPLC-UV a reliable and suitable alternative to the mouse bioassay.

  19. Effects of Coated on Fresh-keeping of Partially Frozen Ruditapes Variegata%涂膜对微冻杂色蛤的保鲜作用

    Institute of Scientific and Technical Information of China (English)

    齐凤生; 刘红英

    2013-01-01

    以pH值、细菌总数、挥发性盐基氮(TVB-N)、硫代巴比妥酸值(TBA)、Ca2+-ATPase活性等为鲜度指标,研究壳聚糖、海藻胶在-3℃条件下对杂色蛤的保鲜效果.试验结果表明:经壳聚糖、海藻胶处理的杂色蛤肉再进行微冻冷藏,其pH值、细菌总数、TVB-N值、TBA值明显低于对照品,Ca2+-ATPase活性明显高于对照品.可食性涂膜在杂色蛤微冻保鲜过程中能有效抑制细菌繁殖,减缓脂肪氧化,延缓腐败变质,从而延长杂色蛤的保鲜期.%This article focuses on the effects on the preservation of Ruditapes variegata, which are seperately treated at the temperature of -3℃ with chitosan and sodium alginate. In the experiments, such acquired indices as pH, total bacterial counts, Total Volatile Base Nitrogen(TVB-N), the 2-thiobarbituric acid(TBA), Ca2+-ATPase activity experiments turn out to be much lower than those of the samples, while Ca2+-ATPase activity higher than that of the samples. So it can be concluded that edible coatings can function effectively in restraint of bacterial reproduction, relief of fat oxidation, and putting off decay, extending their freshness preservation period.

  20. Spatio-temporal variations in biochemical composition, condition index and percentage edibility of the clam, Paphia malabarica (Chemnitz) from estuarine regions of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Nagvenkar, S.S.; Jagtap, T.G.

    Biochemical compositions, condition index (CI) and percentage edibility (PE) of an estuarine clam, Paphia malabarica, were studied from two estuarine regions of Goa during March 2009 to March 2010. Relationships between nutritive components...

  1. Abundance of Vibrio cholerae, V. vulnificus, and V. parahaemolyticus in oysters (Crassostrea virginica) and clams (Mercenaria mercenaria) from Long Island sound.

    Science.gov (United States)

    Jones, Jessica L; Lüdeke, Catharina H M; Bowers, John C; DeRosia-Banick, Kristin; Carey, David H; Hastback, William

    2014-12-01

    Vibriosis is a leading cause of seafood-associated morbidity and mortality in the United States. Typically associated with consumption of raw or undercooked oysters, vibriosis associated with clam consumption is increasingly being reported. However, little is known about the prevalence of Vibrio spp. in clams. The objective of this study was to compare the levels of Vibrio cholerae, Vibrio vulnificus, and Vibrio parahaemolyticus in oysters and clams harvested concurrently from Long Island Sound (LIS). Most probable number (MPN)-real-time PCR methods were used for enumeration of total V. cholerae, V. vulnificus, V. parahaemolyticus, and pathogenic (tdh(+) and/or trh(+)) V. parahaemolyticus. V. cholerae was detected in 8.8% and 3.3% of oyster (n = 68) and clam (n = 30) samples, with levels up to 1.48 and 0.48 log MPN/g in oysters and clams, respectively. V. vulnificus was detected in 97% and 90% of oyster and clam samples, with median levels of 0.97 and -0.08 log MPN/g, respectively. V. parahaemolyticus was detected in all samples, with median levels of 1.88 and 1.07 log MPN/g for oysters and clams, respectively. The differences between V. vulnificus and total and pathogenic V. parahaemolyticus levels in the two shellfish species were statistically significant (P V. vulnificus and total and pathogenic V. parahaemolyticus are more prevalent and are present at higher levels in oysters than in hard clams. Additionally, the data suggest differences in vibrio populations between shellfish harvested from different growing area waters within LIS. These results can be used to evaluate and refine illness mitigation strategies employed by risk managers and shellfish control authorities.

  2. Comparative Study of the Accumulation of Ni in Different Tissues of Mussels and Soft Clams

    Directory of Open Access Journals (Sweden)

    Chalkiadakis O.

    2013-04-01

    Full Text Available Two bivalves, the mussel Mytilus galloprovincialis, and the soft clam Callista chione were exposed to various Ni concentrations for a total period of 20 days, and then a depuration period of 10 days followed. Nickel accumulation in gills, mantle and the remaining body of the animals was measured after 5, 10, 15 and 20 days of exposure to Ni-contaminated seawater. The two organisms showed different behavior regarding Ni accumulation in all three tissues examined. In all concentrations, Ni accumulation increased with time in all three tissues of Mytilus galloprovincialis with gills being the most effective accumulator per dry mass. On the other hand, Callista chione showed an initial response to Ni contamination the first 5 days, followed by stabilization or even a slight decrease of Ni accumulation.

  3. Combined proteomic and metallomic analyses in Scrobicularia plana clams to assess environmental pollution of estuarine ecosystems.

    Science.gov (United States)

    González-Domínguez, Raúl; Santos, Hugo Miguel; Bebianno, Maria João; García-Barrera, Tamara; Gómez-Ariza, José Luis; Capelo, José Luis

    2016-12-15

    Estuaries are very important ecosystems with great ecological and economic value, but usually highly impacted by anthropogenic pressure. Thus, the assessment of pollution levels in these habitats is critical in order to evaluate their environmental quality. In this work, we combined complementary metallomic and proteomic approaches with the aim to monitor the effects of environmental pollution on Scrobicularia plana clams captured in three estuarine systems from the south coast of Portugal; Arade estuary, Ria Formosa and Guadiana estuary. Multi-elemental profiling of digestive glands was carried out to evaluate the differential pollution levels in the three study areas. Then, proteomic analysis by means of two-dimensional gel electrophoresis and mass spectrometry revealed twenty-one differential proteins, which could be associated with multiple toxicological mechanisms induced in environmentally stressed organisms. Accordingly, it could be concluded that the combination of different omic approaches presents a great potential in environmental research.

  4. Diarrhetic shellfish poisoning toxin esters in Danish blue mussels and surf clams

    DEFF Research Database (Denmark)

    Jørgensen, Kevin; Scanlon, Sine Hedegaard; Jensen, L.B.

    2005-01-01

    Until recently, little focus was given to the presence of diarrhetic shellfish poisoning ( DSP) toxin esters in seafood products. However, during the last few years, the occurrence of a high percentage of esters of the total amount of DSP toxins present in some seafood products has been observed....... Samples of Danish surf clams ( Spisola spp.) and blue mussels ( Mytilus edulis) from 1999 - 2004 were analysed by liquid chromatography coupled with tandem mass spectrometry ( LC/ MS/ MS) for the presence of DSP toxin esters. The samples contained only okadaic acid and esters of okadaic acid. The level...... of okadaic acid esters of the total okadaic acid equivalents ranged from 21 to 86%, mean 59%. The probability of a high percentage of okadaic acid esters seems to increase with higher amounts of total okadaic acid equivalents in the bivalves. The large prevalence of DSP toxin esters are of particular...

  5. Parasites of the hard clam Meretrix meretrix Linnaeus from Western Johor Straits, Malaysian

    Science.gov (United States)

    Azmi, Nur Fauzana; Ghaffar, Mazlan Abd.; Cob, Zaidi Che

    2014-09-01

    This study describes the apicomplexa as well as other parasites infecting organs/tissues of the hard clam Meretrix meretrix Linnaeus, from Merambong Shoal, Western Johor Straits, Malaysia. Samples were collected randomly by hand picking, in November and December 2013. Histological techniques were performed, stained using Masson's Trichrome protocol and observed under light microscope. The results showed that gonad and gill were the most infected organs followed by digestive gland, intestine and adductor muscle. No pathology condition was observed in the mantle. Histophatological examination showed that the gregarine, Nematopsis, unidentified coccidian and Perkinsus were found in the gill and gonad, and also in the numerous hemocytes. Other pathological conditions such as bacteria-like inclusion and intracellular bacteria were also observed in the same organs. Further investigations are needed particularly on other molluscs present at the study area. Understanding the morphology and pathology of parasites infecting mollusks are very important for management of the resources.

  6. Recruitment constraints in Singapore's fluted giant clam (Tridacna squamosa population--a dispersal model approach.

    Directory of Open Access Journals (Sweden)

    Mei Lin Neo

    Full Text Available Recruitment constraints on Singapore's dwindling fluted giant clam, Tridacna squamosa, population were studied by modelling fertilisation, larval transport, and settlement using real-time hydrodynamic forcing combined with knowledge of spawning characteristics, larval development, behaviour, and settlement cues. Larval transport was simulated using a finite-volume advection-diffusion model coupled to a three-dimensional hydrodynamic model. Three recruitment constraint hypotheses were tested: 1 there is limited connectivity between Singapore's reefs and other reefs in the region, 2 there is limited exchange within Singapore's Southern Islands, and 3 there exist low-density constraints to fertilisation efficacy (component Allee effects. Results showed that connectivity among giant clam populations was primarily determined by residual hydrodynamic flows and spawning time, with greatest chances of successful settlement occurring when spawning and subsequent larval dispersal coincided with the period of lowest residual flow. Simulations suggested poor larval transport from reefs located along the Peninsular Malaysia to Singapore, probably due to strong surface currents between the Andaman Sea and South China Sea combined with a major land barrier disrupting larval movement among reefs. The model, however, predicted offshore coral reefs to the southeast of Singapore (Bintan and Batam may represent a significant source of larvae. Larval exchange within Singapore's Southern Islands varied substantially depending on the locations of source and sink reefs as well as spawning time; but all simulations resulted in low settler densities (2.1-68.6 settled individuals per 10,000 m(2. Poor fertilisation rates predicted by the model indicate that the low density and scattered distribution of the remaining T. squamosa in Singapore are likely to significantly inhibit any natural recovery of local stocks.

  7. Application of monoclonal antibody against granulocytes of scallop Chlamys farreri on granulocytes occurrence at different developmental stages and antigenic cross-reactivity of granulocytes in five other bivalve species.

    Science.gov (United States)

    Xing, Jing; Tang, Xiaoqian; Ni, Yongqing; Zhan, Wenbin

    2014-01-01

    A monoclonal antibody (MAb) 6H7 raised specifically against granulocytes of scallop (Chlamys farreri) was employed to observe granulocyte occurrence successively in blastulae, gastrulae, trochophore larvae, D-shape larvae, umbo-veliger larvae and creeping larvae of C. farreri by immunohistochemistry assay contrasted with H&E stain using semi-thin sections. Moreover, the reactivity of the MAb with granulocytes of C. farreri, Bay scallop Argopecten irradians, Japanese scallop Patinopecten yessoensis, Blue mussel Mytilus edulis, Pacific oyster Crassostrea gigas and Manila clam Ruditapes philippinarum, was detected by immunofluorescence assay (IFA) with differential interference contrast and fluorescent microscopy and flow cytometric immunofluorescence assay (FCIFA). The results showed that positive signals were first observed at D-shape larval stage, about 28 h post fertilization, after that, umbo-veliger larvae exhibited the positive cells with a diameter of 3-5 μm distributed in velum, digestive gland and esophagus. Then in creeping larvae, the number of positive cells increased with average diameter of 5-7 μm, and widely distributed in foot, digestive gland, gills and adductor muscles. No positive signal was found in blastulae, gastrulae and trochophore larvae. The results of IFA and FCIFA showed MAb 6H7 reacted to granulocytes of C. farreri, A. irradians, P. yessoensis and C. gigas, and the positive percentage reactivity were 53 ± 2.5%, 15 ± 2.5%, 12 ± 2.1% and 19 ± 2.1%, respectively, however, no cross-reaction was detected in hemocytes of R. philippinarum and M. edulis.

  8. Systems-level modeling the effects of arsenic exposure with sequential pulsed and fluctuating patterns for tilapia and freshwater clam

    Energy Technology Data Exchange (ETDEWEB)

    Chen, W.-Y. [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Tsai, J.-W. [Institute of Ecology and Evolutionary Ecology, China Medical University, Taichung 40402, Taiwan (China); Ju, Y.-R. [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Liao, C.-M., E-mail: cmliao@ntu.edu.t [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2010-05-15

    The purpose of this paper was to use quantitative systems-level approach employing biotic ligand model based threshold damage model to examine physiological responses of tilapia and freshwater clam to sequential pulsed and fluctuating arsenic concentrations. We tested present model and triggering mechanisms by carrying out a series of modeling experiments where we used periodic pulses and sine-wave as featured exposures. Our results indicate that changes in the dominant frequencies and pulse timing can shift the safe rate distributions for tilapia, but not for that of freshwater clam. We found that tilapia increase bioenergetic costs to maintain the acclimation during pulsed and sine-wave exposures. Our ability to predict the consequences of physiological variation under time-varying exposure patterns has also implications for optimizing species growing, cultivation strategies, and risk assessment in realistic situations. - Systems-level modeling the pulsed and fluctuating arsenic exposures.

  9. Microstructure and microhardness of CLAM steel irradiated up to 20.8 dpa in STIP-V

    Science.gov (United States)

    Peng, Lei; Ge, Hongen; Dai, Yong; Huang, Qunying; Ye, Minyou

    2016-01-01

    Specimens of China low activation martensitic (CLAM) steel were irradiated in the fifth experiment of SINQ target irradiation program (STIP-V) up to 20.8 dpa/1564 appm He. Microhardness measurements and transmission electron microscope (TEM) observations have been performed to investigate irradiation induced hardening effects. The results of CLAM steel specimens show similar trend in microhardness and microstructure changes with irradiation dose, compared to F82H/Optimax-A steels irradiated in STIP-I/II. Defects and helium bubbles were observed in all specimens, even at a very low dose of 5.4 dpa. For defects and bubbles, the mean size and number density increased with increasing irradiation dose to 13 dpa, and then the mean size increased and number density decreased with the increasing irradiation dose to 20.8 dpa.

  10. Developmental Transcriptome Analysis and Identification of Genes Involved in Larval Metamorphosis of the Razor Clam, Sinonovacula constricta.

    Science.gov (United States)

    Niu, Donghong; Wang, Fei; Xie, Shumei; Sun, Fanyue; Wang, Ze; Peng, Maoxiao; Li, Jiale

    2016-04-01

    The razor clam Sinonovacula constricta is an important commercial species. The deficiency of developmental transcriptomic data is becoming the bottleneck of further researches on the mechanisms underlying settlement and metamorphosis in early development. In this study, de novo transcriptome sequencing was performed for S. constricta at different early developmental stages by using Illumina HiSeq 2000 paired-end (PE) sequencing technology. A total of 112,209,077 PE clean reads were generated. De novo assembly generated 249,795 contigs with an average length of 585 bp. Gene annotation resulted in the identification of 22,870 unigene hits against the NCBI database. Eight unique sequences related to metamorphosis were identified and analyzed using real-time PCR. The razor clam reference transcriptome would provide useful information on early developmental and metamorphosis mechanisms and could be used in the genetic breeding of shellfish.

  11. Reproductive Biology of the Short-Necked Clam, Paphia undulata (Born 1778 from Southern Negros Occidental, Central Philippines

    Directory of Open Access Journals (Sweden)

    Fenelyn M. Nabuab

    2010-12-01

    Full Text Available The short-necked clam, Paphia undulata, occurs in coastal muddy bottoms of Hinigaran, Binalbagan, and Himamaylan, Negros Occidental where it has an important contribution to fisheries. However, stocks in these areas are dwindling and in order to formulate sound management strategies, information on the reproductive biology of this species is a prerequisite. Also, knowledge on the reproduction of this species is a prelude to its laboratory breeding and rearing. Reproductive biology of the short-necked clam from the three areas was studied over an annual cycle. Short-necked clams were collected monthly from catches of compressor divers. Five gonad stages were described based on histological examinations: developing, mature, partially spawned, redeveloping, and spent. Immature or indeterminate gonads were also noted. Although occasional presence of hermaphrodite gonads was observed this species is still functionally dioecious with 1.00M: 1.02F sex ratio. Sexual maturity is attained at 42.6 mm for males and 44.8 mm for females. Short-necked clams have continuous breeding season. However, peak of spawning activities is on the months of August to November which coincide with the monsoon transition months probably due to the decrease in salinity and nutrient influx during these months. Organisms smaller than 45mm must not be collected and collection must be regulated during peaks of spawning activities to leave a portion of reproductively mature individuals to ensure sustainability of fisheries. However, in terms of laboratory breeding and rearing of this species, it is fundamental to consider the spawning peaks and size at sexual maturity to ensure successful spawning in the laboratory. Hence, broodstock to be used in the experiments must be sexually mature (>45mm and collected during peaks of spawning activities.

  12. Identification of larvae: The zebra mussel (Dreissena polymorpha), quagga mussel (Dreissena rosteriformis bugensis), and Asian clam (Corbicula fluminea)

    Science.gov (United States)

    Nichols, S. Jerrine; Black, M.G.

    1994-01-01

    There are presently four freshwater bivalves in the United States that produce larvae or veligers commonly found in the water column: two forms of Asian clams and two species of dreissenids. Portions of the geographic range of three of these bivalves, one species of Asian clam (Corbicula fluminea), zebra mussels (Dreissena polymorpha), and quagga mussels (Dreissena rosteriformis bugensis), overlap, causing problems with larval identification. To determine which characteristics can be used to separate larval forms, adult Asian clams, quaggas, and zebra mussels were brought into the laboratory and induced to spawn, and the resulting larvae were reared. Hybrids between quaggas and zebra mussels were also produced, but not reared to maturity. Characteristics allowing for the most rapid and accurate separation of larvae were hinge length, shell length/height, shell shape, shell size, and the presence or absence of a foot and velum. These characteristics were observed in laboratory-reared larvae of known parentage and field-caught larvae of unknown parentage. In most cases, larvae of the Asian clam can be readily separated from those produced by either type of dreissenid on the basis of shell size and presence of a foot. Separating the gametes and embryos of the two types of dreissenids is not possible, but after shell formation, most of the larval stages can be distinguished. Hinge length, shell length/height, and the similarity in size of the shell valves can be used to separate straight-hinged, umbonal, pediveliger, and plantigrade larvae. Quagga × zebra mussel hybrids show characteristics of both parents and are difficult to identify.

  13. 清洁疏浚物掩埋对菲律宾蛤仔成体的存活影响%Effects of clean dredging materials bury on Ruditapes philippinaru

    Institute of Scientific and Technical Information of China (English)

    季晓; 徐韧; 刘玉; 刘材材; 刘志国; 刘守海; 马永存

    2013-01-01

    为评价不同粒度、不同掩埋深度的疏浚物对于底栖生物潜在影响,采用长江口疏浚物模拟不同粒度、不同深度掩埋菲律宾蛤仔,并研究其存活情况。结果表明,菲律宾蛤仔掩埋后为了生存表现出垂直迁移行为,粒度在0.125~0.063 mm时菲律宾蛤仔表现出较强的迁移能力,存活率大大的提高,掩埋深度在4 cm以下时菲律宾蛤仔全部迁移至疏浚物的表面存活;不同粒度疏浚物掩埋深度在一定范围内与菲律宾蛤仔的死亡率之间有显著的正相关关系。粒度为0.125~0.063 mm时其半致死深度最大,8d-LC50为8.4 cm (95%置信区间5.3~11.6 cm)。实验表明,疏浚物处置后的粒度、沉积厚度对于底栖生物种群的存亡具有重要的作用。%To evaluate different grain sizes and different burial depths of the dredging materials for benthos potential impact, Ruditapes philippinaru was selected to test the burying effect. The experiment results showed that Ruditapes philippinaru could survive by vertically migrating out of the dredging material surface. When the grain size of the dredging materials was 0.125~0.063 mm, it had stronger migration,and the survival rate was greatly improved. When burying depth was under 4 cm, they were all migrated out of the surface and existed well. Different grain size of burying material date analysis proved that there was significant correlation between certain burial depths and mortality of Ruditapes philippinaru. When the size of burying material was 0.125~0.063 mm, it had the biggest LC50. The 8d-LC50 was 8.4 cm, and 95%confidence interval was 5.3~11.6 cm. The study proved that the grain size and the burial depth were important factors for the survival of benthos.

  14. Surface and internal microstructure damage of He-ion-irradiated CLAM steel studied by cross-sectional transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, P.P. [School of Material Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhan, Q., E-mail: qzhan@mater.ustb.edu.cn [School of Material Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Fu, Z.Y.; Wei, Y.P. [School of Material Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Wang, Y.M. [Faculty of Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Wang, F.M. [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Ohnuki, S. [Faculty of Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Wan, F.R. [School of Material Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

    2015-11-15

    Good understanding of blistering and embrittlement mechanism depends on good investigation of surface and internal microstructure damage of gas-ion-irradiated materials. Internal and surface microstructure of He{sup +} ion irradiated CLAM steel were examined by cross-sectional transmission electron microscopy combining focused ion beam. Variation of helium bubble density and size distribution versus depth in CLAM steel after high dose helium irradiation at room temperature was investigated. The average size of helium bubble increased within 100–400 nm but decreased near the non-irradiated matrix with the increase of depth, while the density followed a reverse trend. The formation and growth mechanism of helium bubble is different at different irradiation depth. The formation of a zone of large bubbles under the surface is the main reason of surface blistering and flaking. Helium induced irradiation swelling and surface blistering at low temperature were also discussed. - Highlights: • Microstructure of helium irradiated CLAM steel was investigated by FIB and TEM. • The nucleation of helium bubble was controlled by both different mechanisms. • The substructure of surface blisters has been analyzed in detail by XTEM. • Helium induced surface blistering and irradiation swelling have been discussed.

  15. Study of the toxic effects of flame retardant PBDE-47 on the clam Chamelea gallina (Linnaeus, 1758

    Directory of Open Access Journals (Sweden)

    Salvatora Angela Angioni

    2013-03-01

    Full Text Available The purpose of the study is to evaluate the effects of 2,2',4,4'-tetrabromodiphenylether (PBDE-47 on the Chamelea gallina clam (according to current commercial regulations: Venus gallina. PBDEs, which are used as flame retardants in various industrial products, are classed as hazardous substances by Directive 2011/65/EU. They are bioaccumulative compounds, considered to be endocrine disruptors, genotoxic, neurotoxic and practically ubiquitous, and their concentration in the environment has considerably increased in recent years. The aim of this study is to establish the effects of PBDE-47 on Chamelea gallina: toxic power and any harmful effects on the gonads, bioaccumulation capacity in the tissues, and possible entry into the food chain. The research used 96-hour and 21-day experimental tests on clams housed in filtered seawater. The tests were preceded by a period of acclimatisation of the molluscs lasting five to seven days. The clams were fed on seaweed (Dunaliella tertiolecta. The choice of the toxic compound PBDE-47 was based on the high concentration, among the congeners of PBDE, found in some aquatic species. The study demonstrated that the concentration of the contaminant used did not alter the vital functions, cause significant levels of mortality or lead to evident alteration in the gonads of Chamelea gallina. However, the research demonstrated the bioaccumulation capacity of the bivalve mollusc, allowing PBDE-47 to enter the food chain.

  16. Dynamic changes in the accumulation of metabolites in brackish water clam Corbicula japonica associated with alternation of salinity.

    Science.gov (United States)

    Koyama, Hiroki; Okamoto, Seiji; Watanabe, Naoki; Hoshino, Naoshige; Jimbo, Mitsuru; Yasumoto, Ko; Watabe, Shugo

    2015-03-01

    The brackish water clam Corbicula japonica inhabits rivers and brackish waters throughout Japan where the major fishing grounds in the Ibaraki Prefecture, Japan, are located at the Hinuma Lake and Hinuma River. Water salinity in the Lake Hinuma is low and stable due to the long distance from the Pacific Ocean, whereas that in the downstream of the river varies daily due to a strong effect of tidal waters. In the present study, we dissected the gill and foot muscle of brackish water clam collected from these areas, and subjected them to metabolome analysis by capillary electrophoresis-time-of-flight mass spectrometry. More than 200 metabolites including free amino acids, peptides and organic acids were identified, and their amounts from the foot muscle tend to be higher than those from the gill. The principal component analysis revealed that the amount of each metabolite was different among sampling areas and between the gill and foot muscle, whereas no apparent differences were observed between male and female specimens. When the metabolites in the female clam at high salinity were compared with those at low salinity, concentrations of β-alanine, choline, γ-aminobutyric acid, ornithine and glycine betaine were found to be changed in association with salinity. We also compared various metabolites in relation to metabolic pathways, suggesting that many enzymes were involved in their changes depending on salinity.

  17. Relationship between gonad maturation and heavy metal accumulation in the clam, Galatea paradoxa (Born 1778) from the Volta estuary, Ghana.

    Science.gov (United States)

    Adjei-Boateng, D; Obirikorang, K A; Amisah, S; Madkour, H A; Otchere, F A

    2011-12-01

    The relationship between gonadal development and the concentrations of four heavy metals Mn, Zn, Fe and Hg in the tissues of the clam Galatea paradoxa was evaluated at the Volta estuary, Ghana, over an 18-month period. Metal concentrations in the clam tissues were highly variable over the sampling period and seemed to be influenced by the reproductive cycle of the clam. Mn concentrations varied over a wide range from 49 to 867 μg/g and exhibited a significant positive correlation with gonadal development (p = 0.0146, r(2) = 0.3190). Zn and Fe concentrations ranged from 13 to 59 μg/g and 79 to 484 μg/g, respectively and both revealed negative relationships between gonad development and metal accumulation (Zn (p = 0.0554, r(2) = 0.0554) and Fe (p = 0.1040, r(2) = 0.1567)). Hg concentrations ranged from 0.026 to 0.059 μg/g over the sampling period and exhibited a slight positive relationship between gonadal development and metal accumulation (p = 0.0861, r(2) = 0.1730).

  18. A coupled lake-atmosphere model (CLAM) and its application to Lake Kinneret

    Science.gov (United States)

    Pan, Hai

    1999-08-01

    Kinneret is a 166-km2 lake located in Northern Israel, in the central part of the Jordan Valley, a corridor running from north to south, between the Galilee hills in the west and the Golan Heights in the east. Both the Galilee hills and the Golan Heights reach an elevation of about 400 m above mean sea level (MSL), and the lake is about -210 m (MSL). North of the lake is the mountainous area of the Hermon, culminating at about 2800 m (MSL). About 120 km south of it is the Dead Sea, which is about -410 m (MSL), and about 45 km west of it is the Mediterranean Sea. The complexity of the terrain, combined with relatively arid soil and various ground covers surrounding the lake, results in a very complicated system of atmospheric and lake processes. To understand this system, especially the processes affecting the atmosphere and lake dynamics and thermodynamics, and their effects on Lake Kinneret evaporation, a coupled lake-atmosphere model (CLAM) was developed and applied to the lake region. The CLAM is based on the Regional Atmospheric Modeling System (RAMS) and the oceanic S-coordinate Rutgers University Model (SCRUM). Energy, mass, and momentum are conserved at the interface between the atmosphere and the lake, and appropriate balance equations are applied there. In the atmospheric module, two nested grids are employed to simulate Northern Israel at a resolution of 4 x 4 km2, and the near-lake region at a resolution of 1 x 1 km 2. Synoptic conditions obtained from the National Meteorological Center (NMC) reanalysis are assimilated by the model. Soil moisture, which appears to have a significant impact on atmospheric circulation in this region, was transformed from the normalized difference vegetation index (NDVI). Observations collected during two summers above and inside the lake emphasize the good capability of CLAM to simulate surface fluxes and other microclimatic conditions, as well as lake temperature and currents. Although the lake is small (about 12-km wide

  19. Chemical Characterization of the Aerosol During the CLAMS Experiment Using Aircraft and Ground Stations

    Science.gov (United States)

    Castanho, A. D.; Martins, J.; Artaxo, P.; Hobbs, P. V.; Remer, L.; Yamasoe, M.; Fattori, A.

    2002-05-01

    During the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) Experiment Nuclepore filters were collected in two ground stations and aboard the University of Wasghington's Convair 580 Reserarch Aircraft. The two ground stations were chosen in strategic positions to characterize the chemical composition, the mass concentration, black carbon (BC) content, and the absorption properties of the aerosol particles at the surface level. One of the stations was located at the Cheasapeake lighthouse (25 km from the coast) and the other one was located at the Wallops Island. Aerosol particles where collected in two stages, fine (d2.5um) and coarse mode (2.5CLAMS Experiment area. Some of the filters were also submitted to Scanning Electron Microscopy analysis. The particulate matter mass for all the samples were obtained gravimetrically. The concentration of black carbon in the fine filters was optically determined by a broadband reflectance technique. The spectral (from UV to near IR) reflectance in the fine and coarse mode filter were also obtained with a FieldSpec ASD spectrometer. Aerosol elemental characterization (Na through Pb) was obtained by the PIXE (Particle induced X ray emission) analyses of the nuclepore filters. The sources of the aerosol measured at the ground stations were estimated by principal component analyses mainly in the Wallops Island, where a longer time series was collected. One of the main urban components identified in the aerosol during the experiment was sulfate. Black carbon

  20. Effects of biopreservative combined with partial freezing storage on fresh-keeping of Ruditapes variegata%生物保鲜剂结合微冻保藏对杂色蛤肉的保鲜作用

    Institute of Scientific and Technical Information of China (English)

    齐凤生; 李丽娜; 刘红英

    2014-01-01

    Objective To evaluate fresh-keeping effect of the biological preservatives under partial freezing condition. Methods Disposed with lysozyme, nisin and vacuum packaging, the meat of Ruditapes variegata was examined for its total bacterial count(TBC) and evaluated for its physical and chemical index during its storage under the temperature of (-3±0.5)℃, and fresh-keeping effect of the biological preservatives under partial freezing condition was also evaluated. Results The results showed that after storage under the temperature of -3 ℃ for 25 d, total volatile basic nitrogen (TVB-N) of Ruditapes variegata meat was 14.73 mg/100 g and 14.92 mg/100 g respectively for disposing with lysozyme and nisin, which were within the nor-mal health standard of the national regulation. For the match-up of the two biological preservatives, TVB-N of Ruditapes variegata meat was 14.38 mg/100g after 30 d storage under -3 ℃, which could keep fresh 15 d longer than control sample. Changes of pH value, TBC, TVB-N, Thibabituric Acid (TBA) and Ca2+-ATPase ac-tivity of each disposed samples were all correlated with storage time (P<0.05). Comparing with other test groups, combined disposing of lysozyme and nisin achieved better fresh-keeping effect. Conclusion Dispos-ing of biological preservatives combined with partial freezing storage proves to effectively prolong the shelf life of Ruditapes variegata meat.%目的:评价生物保鲜剂在微冻条件下的保鲜作用。方法以杂色蛤肉为研究对象,经溶菌酶、乳酸链球菌素及真空包装处理,测定其在(-3±0.5)℃贮藏过程中的细菌总数、理化等指标的变化。结果在-3℃条件下贮藏25 d后,经溶菌酶、乳酸链球菌素处理的杂色蛤肉挥发性盐基氮分别达到了14.73 mg/100 g和14.92 mg/100 g,均接近国家规定的卫生标准;溶菌酶、乳酸链球菌素复合处理的杂色蛤肉贮藏30 d其挥发性盐基氮为14.38 mg/100 g,比未经处理的对照组延长了15 d以

  1. Microcystin uptake and biochemical responses in the freshwater clam Corbicula leana P. exposed to toxic and non-toxic Microcystis aeruginosa: Evidence of tolerance to cyanotoxins

    Directory of Open Access Journals (Sweden)

    Thanh-Luu Pham

    2015-01-01

    Full Text Available We investigated the accumulation and adverse effects of toxic and non-toxic Microcystis in the edible clam Corbicula leana. Treated clams were exposed to toxic Microcystis at 100 μg of MC (microcystin-LReq L−1 for 10 days. The experimental organism was then placed in toxin-free water and fed on non-toxic Microcystis for the following 10 days for depuration. Filtering rates (FRs by C. leana of toxic and non-toxic Microcystis and of the green alga Chlorella vulgaris as a control were estimated. Adverse effects were evaluated though the activity of catalase (CAT, superoxide dismutase (SOD and glutathione S-transferase (GST. Clam accumulated MCs (up to 12.7 ± 2.5 μg g−1 dry weight (DW of free MC and 4.2 ± 0.6 μg g−1 DW of covalently bound MC. Our results suggest that although both toxic and non-toxic cyanobacteria caused adverse effects by inducing the detoxification and antioxidant defense system, the clam was quite resistant to cyanotoxins. The estimated MC concentration in C. leana was far beyond the World Health Organization's (WHO provisional tolerable daily intake (0.04 μg kg−1 day−1, suggesting that consuming clams harvested during cyanobacterial blooms carries a high health risk.

  2. Toxicity and the fractional distribution of trace metals accumulated from contaminated sediments by the clam Scrobicularia plana exposed in the laboratory and the field

    Energy Technology Data Exchange (ETDEWEB)

    Kalman, J., E-mail: judit.kalman@uca.es [Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom); Bonnail-Miguel, E. [Department of Physical-Chemistry, University of Cadiz, Poligono Industrial Rio San Pedro s/n, 11,510 Puerto Real, Cadiz (Spain); Smith, B.D. [Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom); Bury, N.R. [Division of Diabetes and Nutritional Science, King' s College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH (United Kingdom); Rainbow, P.S. [Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom)

    2015-02-15

    The relationship between the subcellular distribution of accumulated toxic metals into five operational fractions (subsequently combined into presumed detoxified and non-detoxified components) and toxicity in the clam Scrobicularia plana was investigated under different laboratory exposures. Clams were exposed to metal contaminated media (water and diet) and analysed for the partitioning of accumulated As, Cu and Zn into subcellular fractions. In general, metallothionein-like proteins, metal-rich granules and cellular debris in different proportions acted as main storage sites of accumulated metals in the clam soft tissues for these three metals. No significant differences were noted in the accumulation rates of As, Cu and Zn of groups of individuals with or without apparent signs of toxicity after up to 30 days of exposure to naturally contaminated sediment mixtures. There was, however, an increased proportional accumulation of Cu in the non-detoxified fraction with increased Cu accumulation rate in the clams, suggesting that the Cu uptake rate from contaminated sediments exceeded the combined rates of elimination and detoxification of Cu, with the subsequent likelihood for toxic effects in the clams. - Highlights: • Scrobicularia plana accumulated As, Cu and Zn from naturally toxic sediments. • Toxic metals were accumulated in detoxified and non-detoxified components. • Cu accumulation in the non-detoxified pool increased with increased Cu uptake rate. • Cu uptake rate exceeded combined loss and detoxification rates to cause toxicity.

  3. Hemoglobins Likely Function as Peroxidase in Blood Clam Tegillarca granosa Hemocytes

    Science.gov (United States)

    Yu, Xiaopei; Lin, Zhihua; Xue, Liangyi

    2017-01-01

    Hemoglobins are a group of respiratory proteins principally functioning in transport of oxygen and carbon dioxide in red blood cells of all vertebrates and some invertebrates. The blood clam T. granosa is one of the few invertebrates that have hemoglobin-containing red hemocytes. In the present research, the peroxidase activity of T. granosa hemoglobins (Tg-Hbs) was characterized and the associated mechanism of action was deciphered via structural comparison with other known peroxidases. We detected that purified Tg-Hbs catalyzed the oxidation of phenolic compounds in the presence of exogenous H2O2. Tg-Hbs peroxidase activity reached the maximum at pH 5 and 35°C and was inhibited by Fe2+, Cu2+, SDS, urea, and sodium azide. Tg-Hbs shared few similarities in amino acid sequence and overall structural characteristics with known peroxidases. However, the predicted structure at their heme pocket was highly similar to that of horseradish peroxidase (HRP) and myeloperoxidase (MPO). This research represented the first systemic characterization of hemoglobin as a peroxidase. PMID:28182094

  4. Preliminary study of HDA coating on CLAM steel followed by high temperature oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiaoqiang, E-mail: newboy.chen@163.com; Huang, Qunying; Yan, Zilin; Song, Yong; Liu, Shaojun; Jiang, Zhizhong

    2013-11-15

    A hot-dip aluminizing process is expected to produce aluminide coatings on structural materials to resist tritium permeation, corrosion, and magnetohydrodynamic (MHD) effects in the fusion reactor blanket. China Low Activation Martensitic (CLAM) steel, which is the candidate structural material for the LiPb blanket system in China, was coated with pure aluminum and with an Al–Si alloy. Factors affecting the thickness and morphology of the aluminide coatings were studied. After the hot-dipping treatment, FeAl{sub 3} and Fe{sub 2}Al{sub 5} were observed at the Al/steel interface. The existence of silicon in the molten aluminum suppressed the growth of Fe{sub 2}Al{sub 5}, built up the thickness of FeAl{sub 3} slightly, and contributed to reducing the thickness of the intermetallic layer. The brittle phase of Fe{sub 2}Al{sub 5} had completely transformed to ductile phases of FeAl{sub 2}, FeAl and α-Fe(Al) after high temperature heat-treatment in air. Kirkendall voids were found in the diffusion layer, due to the rapid interdiffusion of iron and aluminum during oxidation. Cracks and pores were observed on the coating surface and at the interlayer. Grazing incidence X-ray diffraction indicates the presence of α-Al{sub 2}O{sub 3} in the oxide layer.

  5. Molecular phylogenetics and historical biogeography amid shifting continents in the cockles and giant clams (Bivalvia: Cardiidae).

    Science.gov (United States)

    Herrera, Nathanael D; Ter Poorten, Jan Johan; Bieler, Rüdiger; Mikkelsen, Paula M; Strong, Ellen E; Jablonski, David; Steppan, Scott J

    2015-12-01

    Reconstructing historical biogeography of the marine realm is complicated by indistinct barriers and, over deeper time scales, a dynamic landscape shaped by plate tectonics. Here we present the most extensive examination of model-based historical biogeography among marine invertebrates to date. We conducted the largest phylogenetic and molecular clock analyses to date for the bivalve family Cardiidae (cockles and giant clams) with three unlinked loci for 110 species representing 37 of the 50 genera. Ancestral ranges were reconstructed using the dispersal-extinction-cladogenesis (DEC) method with a time-stratified paleogeographic model wherein dispersal rates varied with shifting tectonics. Results were compared to previous classifications and the extensive paleontological record. Six of the eight prior subfamily groupings were found to be para- or polyphyletic. Cardiidae originated and subsequently diversified in the tropical Indo-Pacific starting in the Late Triassic. Eastern Atlantic species were mainly derived from the tropical Indo-Mediterranean region via the Tethys Sea. In contrast, the western Atlantic fauna was derived from Indo-Pacific clades. Our phylogenetic results demonstrated greater concordance with geography than did previous phylogenies based on morphology. Time-stratifying the DEC reconstruction improved the fit and was highly consistent with paleo-ocean currents and paleogeography. Lastly, combining molecular phylogenetics with a rich and well-documented fossil record allowed us to test the accuracy and precision of biogeographic range reconstructions.

  6. Rhodopirellula rosea sp. nov., a novel bacterium isolated from an ark clam Scapharca broughtonii.

    Science.gov (United States)

    Roh, Seong Woon; Lee, Hae-Won; Yim, Kyung June; Shin, Na-Ri; Lee, Jina; Whon, Tae Woong; Lim, Na-Lae; Kim, Daekyung; Bae, Jin-Woo

    2013-06-01

    A novel Gram-negative, motile, and ovoid-shaped strain, LHWP3(T), which belonged to the family Planctomycetaceae in the phylum Planctomycetes, was isolated from a dead ark clam Scapharca broughtonii collected during a mass mortality event on the south coast of Korea. Phylogenetic analysis based on the 16S rRNA gene sequences indicated that the isolate was most closely related to the type strain of Rhodopirellula baltica, with a shared 16S rRNA gene sequence similarity of 94.8%. The isolate grew optimally at 30°C in 4-6% (w/v) NaCl, and at pH 7. The major isoprenoid quinone was menaquinone-6 (MK-6). The dominant polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, and unidentified polar lipids. The predominant cellular fatty acids were C16:0, C18:1 ω9c, and C18:0. The genomic DNA G+C content of strain LHWP3(T) was 53.0 mol%. Based on polyphasic taxonomic analyses, strain LHWP3(T) should be classified as a novel species in the genus Rhodopirellula in the family Planctomycetaceae, for which the name Rhodopirellula rosea sp. nov. is proposed. The type strain is LHWP3(T) (=KACC 15560(T) =JCM 17759(T)).

  7. Fossil clam shells reveal unintended carbon cycling consequences of Colorado River management

    Science.gov (United States)

    Smith, Jansen A.; Auerbach, Daniel A.; Flessa, Karl W.; Flecker, Alexander S.; Dietl, Gregory P.

    2016-09-01

    Water management that alters riverine ecosystem processes has strongly influenced deltas and the people who depend on them, but a full accounting of the trade-offs is still emerging. Using palaeoecological data, we document a surprising biogeochemical consequence of water management in the Colorado River basin. Complete allocation and consumptive use of the river's flow has altered the downstream estuarine ecosystem, including the abundance and composition of the mollusc community, an important component in estuarine carbon cycling. In particular, population declines in the endemic Colorado delta clam, Mulinia coloradoensis, from 50-125 individuals m-2 in the pre-dam era to three individuals m-2 today, have likely resulted in a reduction, on the order of 5900-15 000 t C yr-1 (4.1-10.6 mol C m-2 yr-1), in the net carbon emissions associated with molluscs. Although this reduction is large within the estuarine system, it is small in comparison with annual global carbon emissions. Nonetheless, this finding highlights the need for further research into the effects of dams, diversions and reservoirs on the biogeochemistry of deltas and estuaries worldwide, underscoring a present need for integrated water and carbon planning.

  8. Seasonal dynamics of biomarkers in infaunal clam Macoma balthica from the Gulf of Riga (Baltic Sea)

    Science.gov (United States)

    Barda, Ieva; Purina, Ingrida; Rimsa, Elina; Balode, Maija

    2014-01-01

    Biomarkers are often regarded as “early warning” signals of environmental pollution; however seasonal changes are mentioned as one of the most important factor that influences the activity of biomarkers. The aim of our study was to assess the importance of seasonal variation of selected contaminant biomarkers in Macoma balthica to provide background information for further environmental surveys in the Gulf of Riga. Seasonal variation of biomarkers (acetylcholinesterase (AChE), catalase (CAT), glutathione reductase (GR) and glutathione-S-transferase (GST)) was measured in infaunal clam M. balthica from the southern part of the Gulf of Riga. The majority of biomarkers (GST, CAT and GR) showed strong seasonal variability; however only CAT and GR were found to be significantly related to environmental factors (near-bottom oxygen, salinity and temperature). Integrated biomarker response (IBR) index indicated that the most stressed condition of M. balthica is during August and May. The highest values of IBR were found near the mouth of the River Daugava, suggesting the impact of environmental pollution on the benthic animals.

  9. Shell matrix proteins of the clam, Mya truncata: Roles beyond shell formation through proteomic study.

    Science.gov (United States)

    Arivalagan, Jaison; Marie, Benjamin; Sleight, Victoria A; Clark, Melody S; Berland, Sophie; Marie, Arul

    2016-06-01

    Mya truncata, a soft shell clam, is presented as a new model to study biomineralization through a proteomics approach. In this study, the shell and mantle tissue were analysed in order to retrieve knowledge about the secretion of shell matrix proteins (SMPs). Out of 67 and 127 shell and mantle proteins respectively, 16 were found in both shell and mantle. Bioinformatic analysis of SMP sequences for domain prediction revealed the presence of several new domains such as fucolectin tachylectin-4 pentraxin-1 (FTP), scavenger receptor, alpha-2-macroglobulin (α2 M), lipocalin and myosin tail along with previously reported SMP domains such as chitinase, carbonic anhydrase, tyrosinase, sushi, and chitin binding. Interestingly, these newly predicted domains are attributed with molecular functions other than biomineralization. These findings suggest that shells may not only act as protective armour from predatory action, but could also actively be related to other functions such as immunity. In this context, the roles of SMPs in biomineralization need to be looked in a new perspective.

  10. Hemoglobins Likely Function as Peroxidase in Blood Clam Tegillarca granosa Hemocytes.

    Science.gov (United States)

    Wang, Sufang; Yu, Xiaopei; Lin, Zhihua; Zhang, Shunqin; Xue, Liangyi; Xue, Qinggang; Bao, Yongbo

    2017-01-01

    Hemoglobins are a group of respiratory proteins principally functioning in transport of oxygen and carbon dioxide in red blood cells of all vertebrates and some invertebrates. The blood clam T. granosa is one of the few invertebrates that have hemoglobin-containing red hemocytes. In the present research, the peroxidase activity of T. granosa hemoglobins (Tg-Hbs) was characterized and the associated mechanism of action was deciphered via structural comparison with other known peroxidases. We detected that purified Tg-Hbs catalyzed the oxidation of phenolic compounds in the presence of exogenous H2O2. Tg-Hbs peroxidase activity reached the maximum at pH 5 and 35°C and was inhibited by Fe(2+), Cu(2+), SDS, urea, and sodium azide. Tg-Hbs shared few similarities in amino acid sequence and overall structural characteristics with known peroxidases. However, the predicted structure at their heme pocket was highly similar to that of horseradish peroxidase (HRP) and myeloperoxidase (MPO). This research represented the first systemic characterization of hemoglobin as a peroxidase.

  11. Physical proximity may promote lateral acquisition of bacterial symbionts in vesicomyid clams.

    Directory of Open Access Journals (Sweden)

    Carole Decker

    Full Text Available Vesicomyid clams harbor intracellular sulfur-oxidizing bacteria that are predominantly maternally inherited and co-speciate with their hosts. Genome recombination and the occurrence of non-parental strains were recently demonstrated in symbionts. However, mechanisms favoring such events remain to be identified. In this study, we investigated symbionts in two phylogenetically distant vesicomyid species, Christineconcha regab and Laubiericoncha chuni, which sometimes co-occur at a cold-seep site in the Gulf of Guinea. We showed that each of the two species harbored a single dominant bacterial symbiont strain. However, for both vesicomyid species, the symbiont from the other species was occasionally detected in the gills using fluorescence in situ hybridization and gene sequences analyses based on six symbiont marker genes. Symbiont strains co-occurred within a single host only at sites where both host species were found; whereas one single symbiont strain was detected in C. regab specimens from a site where no L. chuni individuals had been observed. These results suggest that physical proximity favored the acquisition of non-parental symbiont strains in Vesicomyidae. Over evolutionary time, this could potentially lead to genetic exchanges among symbiont species and eventually symbiont displacement. Symbiont densities estimated using 3D fluorescence in situ hybridization varied among host species and sites, suggesting flexibility in the association despite the fact that a similar type of metabolism is expected in all symbionts.

  12. Overfishing population characteristics of razor clam, Ensis macha, from Independencia Bay, Peru, in 2004 year

    Directory of Open Access Journals (Sweden)

    Juan Tarazona

    2011-05-01

    Full Text Available Quantitative monthly samplings, in 2004, were carried out to estimate the density and biomass of Ensis macha (Molina 1782, from Morro Quemado area, Bay Independence, Pisco. The present study analyzes biometric relationships, growth parameters and somatic production using the ELEFAN I routine and the Crisp’s method. During the year 2004 the rate of exploitation (E= 0.69 y-1 was significantly bigger than the values of 2003 and the monthly landings (maximum of 335 t and fishing effort (maximum of 848 trips were twice increased. These changes induced in the same year a significant decrease of population mean density (D= 54.13 ind. m-2 and the halfway reduction of somatic production (P= 81.99 gAFDW m-2 y-1 and P/B rate (0.38 y-1 values, regarding the values of the previous year. Also, a significant increment of total mortality rate (2.84 y-1 and the fishing mortality rate (1.97 y-1 were twice increased, regarding the previous year. It is assumed that the population of razor clams already was a overfishing commercial resource in the 2003 and that the increment of fishing pressure in the 2004, particularly during the second semester, intensified its overfishing resource condition.

  13. Molecular phylogeny of the genus Ruditapes (Mollusca: Bivalvia) based on mitochondrial 16S and COI sequences%两种蛤仔线粒体16SrRNA基因和CO I基因的序列比较

    Institute of Scientific and Technical Information of China (English)

    刘相全; 包振民; 方建光; 王如才

    2011-01-01

    DNA sequence comparisons of two mitochondrial DNA genes were used to infer phylogenetic relationships of the genus Ruditapes. The 16S rRNA gene displayed 117 variable sites and the CO I gene displayed 160. There were 29 variable amino acid residues among the 219 of the CO I gene. Phylogenetic analysis using sequences of 16S rRNA gene and CO I gene yielded trees with different topology. More sequences among more species of subfamily Tapetinae would contribute to improve existing classification systems.%对菲律宾蛤仔(Ruditapes philippinarum)和杂色蛤仔(Ruditapes variegata)的线粒体16SrRNA基因和CO I基因序列进行了分析。结果表明,16S序列共有117个变异位点,CO I序列共有160个变异位点,CO I基因编码的219个氨基酸序列中有29个不同。根据16S序列和CO I基因编码的氨基酸序列进行聚类分析,两种蛤仔与硬壳蛤(Mercenaria mercenaria)之间的聚类结果并不一致,有必要对缀锦蛤亚科更多的相近种进行序列分析。

  14. Favored use of anti-predator netting (APN) applied for the farming of clams leads to little benefits to industry while increasing nearshore impacts and plastics pollution.

    Science.gov (United States)

    Bendell, L I

    2015-02-15

    An overview of the efficacy of anti-predator netting (APN) used by the shellfish industry is presented. There is little support that the currently favored APN effectively protects farmed clams from predators. Evidence does suggest that APN leads to impacts and pollution. APN is an attractant for predators, e.g., crabs, by providing a refuge within Ulva sp. which attaches onto the surface of APN. APN entrains silt and organic matter and increases sediment temperatures degrading habitat underneath the APN. APN present hazards to fish and wildlife and is a source of plastics to the marine environment. The continued use of ineffective APN does not serve either the environment or industry well, and many of these issues could be addressed through the alternate use of "ancient" technology used by aboriginal people to maintain clam gardens; building of rock walls optimizing the amount of clam habitat thereby increasing numbers without the use of APN.

  15. Temporal trends of coastal environment along Japan as revealed by mussel watch and specimen bank

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, Y.; Yoshinaga, J.; Horiguchi, T.; Uehiro, T.; Morita, M. [National Inst. of Environmental Studies, Tsukuba, Ibaraki (Japan)

    1995-12-31

    Mussel watch program coupled with a pilot specimen bank at NIES was conducted from 1983 to 1987, and also from 1993 to 1994, and their results were compared to reveal temporal trends of coastal environment along Japan. Special emphasis was paid to reveal the change of ``background`` level of pollutants by collecting bivalves in remote islands. Several species of mussels (Mytilus edulis galloprovincialis, M. coruscus, Septifer virgatus, Pema viridis), oysters (Saxostrea mordax, Crassostrea gigas) and clams (Ruditapes philippinarum, Tridacna crocea) were collected to cover subfrigid to subtropical zones along Japan islands. The level of TBT decreased considerably between the above two intervals, i.e., from 0.12--0.01 {micro}g/g in mid 80`s to 0.03-n.d. (less than 0.01) {micro}g/g in 1993. This decrease may reflect the start of the regulation in 1990. The clam samples collected at Tokyo bay and stored in specimen bank were found to contain considerable levels (near 0.3 {micro}g/g) of TBT and TPT in 1980, and their levels were almost constant through mid and late 1980`s. Several heavy metals, including Cd, showed interesting spatial distribution patterns; their concentrations tend to be higher in less populated remote islands in western part of Japan than in densely populated areas. Cd concentrations, however, also show apparent correlation with Zn status of each organism (especially evident in Septifer sp.), and the interpretation of the results is not straightforward at this stage. Interestingly, a tropical green mussel, P. viridis, was found to be spreading in some densely populated area including Tokyo and Osaka bays.

  16. Insights into the establishment of the Manila clam on a tidal flat at the southern end of an introduced range in Southern California, USA.

    Directory of Open Access Journals (Sweden)

    Drew M Talley

    Full Text Available Coastal ecosystem modifications have contributed to the spread of introduced species through alterations of historic disturbance regimes and resource availability, and increased propagule pressure. Frequency of occurrence of the Manila clam (Venerupis phillipinarum, Veneridae in Southern California estuaries has increased from absent or sparse to common since the mid-1990s. Potential invasion vectors include seafood sales and aquaculture, and spread from established northern populations over decades. The clam's post-settlement habitat preferences are, however, uncertain in this region. Our project aimed to identify factors associated with established patches of the clam within a bay toward the southern end of this introduced range. During summer 2013, we sampled 10 tidal flat sites in Mission Bay, San Diego; each containing an area with and without hard structure (e.g., riprap, boulders. We measured likely environmental influences (e.g., sediment variables, distance to ocean. Manila clam densities across the bay were most strongly associated with site, where highest densities were located in the northern and/or back halves of the bay; and weakly correlated with lower porewater salinities. Within sites, Manila clam density was enhanced in the presence of hard structure in most sites. Prevailing currents and salinity regimes likely contribute to bay wide distributions, while hard structures may provide suitable microhabitats (refuge from predators and physical stress and larval entrapment within sites. Results provide insights into decisions about future shoreline management efforts. Finally, we identify directions for future study to better understand and therefore predict patterns of establishment of the Manila clam in the southern portion of its introduced range.

  17. Can ecological history influence response to pollutants? Transcriptomic analysis of Manila clam collected in different Venice lagoon areas and exposed to heavy metal.

    Science.gov (United States)

    Milan, Massimo; Matozzo, Valerio; Pauletto, Marianna; Di Camillo, Barbara; Giacomazzo, Matteo; Boffo, Luciano; Binato, Giovanni; Marin, Maria Gabriella; Patarnello, Tomaso; Bargelloni, Luca

    2016-05-01

    Chronic exposure to environmental pollutants can exert strong selective pressures on natural populations, favoring the transmission over generations of traits that enable individuals to survive and thrive in highly impacted environments. The lagoon of Venice is an ecosystem subject to heavy anthropogenic impact, mainly due to the industrial activities of Porto Marghera (PM), which led to a severe chemical contamination of soil, groundwater, and sediments. Gene expression analysis on wild Manila clams collected in different Venice lagoon areas enabled to identify differences in gene expression profiles between clams collected in PM and those sampled in clean areas, and the definition of molecular signatures of chemical stress. However, it remains largely unexplored to which extent modifications of gene expression patterns persists after removing the source of contamination. It is also relatively unknown whether chronic exposure to xenobiotics affects the response to other chemical pollutants. To start exploring such issues, in the present study a common-garden experiment was coupled with transcriptomic analysis, to compare gene expression profiles of PM clams with those of clams collected in the less impacted area of Chioggia (CH) during a period under the same control conditions. Part of the two experimental groups were also exposed to copper for seven days to assess whether different "ecological history" does influence response to such pollutant. The results obtained suggest that the chronic exposure to chemical pollution generated a response at the transcriptional level that persists after removal for the contaminated site. These transcriptional changes are centered on key biological processes, such as defense against either oxidative stress or tissue/protein damage, and detoxification, suggesting an adaptive strategy for surviving in the deeply impacted environment of Porto Marghera. On the other hand, CH clams appeared to respond more effectively to copper

  18. The impact of selection on population genetic structure in the clam Meretrix petechialis revealed by microsatellite markers.

    Science.gov (United States)

    Lu, Xia; Wang, Hongxia; Li, Yan; Liu, Baozhong

    2016-02-01

    The aim of our work is to evaluate the impact of mass selection on genetic structure in artificially closed populations of the clam Meretrix petechialis. In the present study, we performed mass selection over four generations (from 2004 to 2010) on two clam populations [shell features of purple lines (SP) and black dots (SB)] and analyzed their temporal genetic variation and structure using microsatellite makers. The two closed populations originated from the natural Shandong population (SD); thus, a natural SD population (10SD) was used to detect the current genetic structure after 6 years of natural selection. The results showed that the genetic diversity of the four generations of SB and SP was gradually reduced but remained at relatively high levels (SB, A = 18.9.4-16.8, Ho = 0.7389-0.6971, and He = 0.8897-0.8591; SP, A = 20.0-17.8, Ho = 0.7512-0.7043, and He = 0.8938-0.8625), which has not been reduced compared with that of the 10SD population (A = 17.8, Ho = 0.6803, and He = 0.8302). The Ne estimates for the two populations were almost at the same levels as the actual numbers of parental individuals. In addition, a low inbreeding coefficient was detected in the two populations (SB, 0.00201-0.00639; SP, 0.00176-0.00541). Based on the results, the present mass selection has not made a large impact on the population genetic structure of the closed populations. The present investigation provides important information for the development of management strategies for genetic breeding of the clam.

  19. Best management strategies for sustainable giant clam fishery in French Polynesia islands: answers from a spatial modeling approach.

    Directory of Open Access Journals (Sweden)

    Simon Van Wynsberge

    Full Text Available The giant clam Tridacna maxima has been largely overexploited in many tropical regions over the past decades, and was therefore listed in appendix II of the Convention of International Trade in Endangered Species (CITES in 1985. In French Polynesia, several atolls and islands harbor the world's highest stocks of giant clams in very shallow and accessible areas, which are therefore highly vulnerable to fishing pressure. The local fishery authority (i.e., Direction des Resources Marines or "DRM" implemented several management schemes in 2002 to control and regulate fishing pressure. However, for further decisions DRM was missing a sensitivity analysis on the effectiveness of the possible management actions. Here, we report on the use of a deterministic Viable Population Analysis (VPA and spatially-explicit age-based population model that simulated the 30-year trajectory of a Tridacna maxima stock under different management approaches. Specifically, given various scenarios of intra-island larval dispersal, we tested which of No-take-Areas (NTAs, rotational closures, size limits, quotas, and restocking schemes would lead to the highest future stocks in Tubuai and Raivavae, two exploited islands of the Austral archipelago. For both islands, stock abundances were estimated in 2004/2010 and 2005/2010 respectively, and natural mortalities were assessed previously only in Tubuai. When compared to field data, the model successfully predicted the 2010 stocks for Tubuai, but proved to be less reliable for Raivavae, where natural mortality rates may well be different from those on Tubuai. For Tubuai, the spatial model suggested that reducing fishing effort (through fixed quotas and banning fishing below the 12 cm size limit (as currently implemented were the most effective management actions to sustain T. maxima populations into the future. Implementing NTAs was of poor effectiveness. NTAs increased giant clam stock inside the protected area, but also

  20. Haemocytic leukemia in Prince Edward Island (PEI) soft shell clam (Mya arenaria): Spatial distribution in agriculturally impacted estuaries

    Energy Technology Data Exchange (ETDEWEB)

    Muttray, Annette, E-mail: amuttray@rescan.com [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Reinisch, Carol, E-mail: creinisch@mbl.edu [Visiting Scientist Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Miller, Jason, E-mail: j.miller@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Ernst, William, E-mail: bill.ernst@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 45 Alderney Drive, Dartmouth, NS, Canada B2Y 2N6 (Canada); Gillis, Patricia, E-mail: patty.gillis@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Losier, Melanie, E-mail: melanie.losier@ec.gc.ca [Environment Canada, Atlantic Laboratory for Environmental Testing, Environmental Science Centre, P.O. Box 23005 Moncton, NB, Canada E1A 6S8 (Canada); Sherry, James, E-mail: jim.sherry@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada)

    2012-05-01

    Intensive farming of potatoes in Prince Edward Island (PEI) relies on the repeated and widespread application of fertilizers and pesticides. In PEI the main potato farming areas are in close proximity and drain directly to estuaries. Runoff from high agricultural activity watersheds could impact benthic organism health in the depositional zone of downstream estuaries. The estuarine filter feeder Mya arenaria (soft-shell clam) could be particularly vulnerable to both particle-adsorbed and water soluble contaminants. M. arenaria is susceptible to haemocytic leukemia. In May 2009, we established that heavily proliferated leukemia (HPL) prevalence was generally higher in PEI estuaries located downstream of high intensity potato farming (Dunk and Wilmot estuaries) watersheds than in estuaries downstream of lower intensity areas. Using Mab-1E10 based immunocytochemistry we observed that leukemic haemocytes from the Dunk and Wilmot estuaries were 1E10 negative whereas those from the Ox/Sheep estuary (low potato farming intensity) were 1E10 positive. The expression of genes in the p53 tumour suppressor pathway enabled us to differentiate groups of leukemic and normal M. arenaria, validating our diagnoses. In October 2009, we confirmed that HPL prevalence was elevated in the Dunk and Wilmot estuaries compared to reference (Souris River). Moreover, leukemia prevalence declined with distance from the river mouths along transects through the Dunk and Wilmot estuaries. The pesticides ss-endosulfan and {alpha}-endosulfan were detected in surface sediments from the Dunk and Wilmot estuaries, but not in sediments from either the Souris River or several other lower intensity potato farming watersheds. Our study provides evidence of an association between intensity of potato farming and prevalence of clam leukemia at downstream estuaries in PEI. - Highlights: Black-Right-Pointing-Pointer We examined leukemia prevalence in PEI clams Mya arenaria. Black

  1. Baseline of organotin pollution in fishes, clams, shrimps, squids and crabs collected from the west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Jadhav, S.; Bhosale, D.; Bhosle, N.B.

    is available. The present study was planned to assess organotin contamination levels in edible marine organisms collected from the fish markets of Goa, Karwar and Mumbai, the west coast of India. The sampling locations: Goa (15.5ºN, 73.9ºE), Karwar (14.8º... of Karwar is around 36,000 tonnes. Mumbai coast is about 140 km long. Mumbai is among busiest harbours on the west coast of India is known for industrial pollution. The fishes, clams, crabs and squids and shrimps were collected from local fish markets...

  2. Early development, survival and growth rates of the giant clam Tridacna crocea (Bivalvia: Tridacnidae

    Directory of Open Access Journals (Sweden)

    Miguel Mies

    2012-06-01

    Full Text Available Tridacnid clams are conspicuous inhabitants of Indo-Pacific coral reefs and are traded and cultivated for the aquarium and food industries. In the present study, daily growth rates of larvae of the giant clam Tridacna crocea were determined in the laboratory during the first week of life. Adults were induced to spawn via intra-gonadal serotonin injection through the byssal orifice. After spawning oocytes were collected, fertilized and kept in 3 L glass beakers and raceways treated with antibiotics to avoid culture contamination. Larvae were fed twice with the microalga Isochrysis galbana and zooxanthellae were also offered twice during the veliger stage (days 4 and 6. Larval length was measured using a digitizing tablet coupled to a microcomputer. Larval mortality was exponential during the first 48 hours of life declining significantly afterwards. Mean growth rate was 11.3 μm day-1, increasing after addition of symbionts to 18.0 μm day-1. Survival increased to ca. 75% after the addition of zooxanthellae. The results describe the growth curve for T. crocea larvae and suggest that the acquisition of symbionts by larvae may be useful for larval growth and survival even before larvae have attained metamorphosis.Bivalves tridacnídeos são habitantes conspícuos dos recifes da região do Indo-Pacífico e são cultivados e comercializados para os mercados alimentício e aquarista. No estudo apresentado foram determinadas as taxas de crescimento diário durante a primeira semana de vida da larva do bivalve ornamental Tridacna crocea. As matrizes foram induzidas à desova por meio de uma injeção intragonadal de serotonina realizada através do orifício bissal. Após desova, ovócitos foram coletados, fertilizados e mantidos em béqueres de vidro e tanques de fluxo contínuo tratados com antibióticos para evitar contaminação. Larvas foram alimentadas em duas ocasiões com a microalga Isochrysis galbana e zooxantelas foram oferecidas também por

  3. First study of Vibrios in larval cultures of pullet carpet shell clam (Venerupis corrugata in hatchery

    Directory of Open Access Journals (Sweden)

    Javier Dubert Pérez

    2014-07-01

    Full Text Available Protocol for hatchery culture of the pullet carpet shell clam Venerupis corrugata spat is currently under development, as the only reliable means of providing spat to replenish natural beds or to support aquaculture activities. Among other variables, the microbiota has been demonstrated to be critical for successful bivalve culture. Shellfish hatcheries are hindered by fatal outbreaks of disease, regardless the bivalve species. These mass mortalities are mainly caused by opportunistic bacteria belonging to genus Vibrio and constitute one bottleneck for this economic activity. Different species, as V. tubiashii, V. pectenicida, V. splendidus, V. neptunius, V. ostreicida and V. bivalvicida, have been identified as responsible of mortalities in hatchery-reared larvae, affecting a wide range of bivalves. This is the first report of the microbiota associated with larval cultures of the pullet carpet shell clam. We present the results of the microbiological analyses of two larval cultures of pullet carpet shell reared in the Centro de Investigacións Mariñas (CIMA, Xunta de Galicia de Ribadeo (Galicia, NW Spain following the procedures developed in the institution. Each batch, A and B, was obtained from broodstocks collected in natural environment but in different geographical locations, the stock A (SW Galicia and the stock B (NW Galicia. Previous records of mortalities led us to divide each batch in two. One sub-batch (A1 and B1 was cultured following the routine procedures. Antibiotic was experimentally added to the other sub-batch (A2 and B2 with the aim of evaluating the effects on the culturable bacterial population (total marine bacteria and presumptive vibrios and on larval survival. Chloramphenicol, formerly the most commonly used antibiotic in bivalve hatcheries, was supplied with each change of seawater during larval development. Microbiological samples of broodstock, larvae and seawater in culture tanks were taken and processed

  4. Ruegeria conchae sp. nov., isolated from the ark clam Scapharca broughtonii.

    Science.gov (United States)

    Lee, Jina; Whon, Tae Woong; Shin, Na-Ri; Roh, Seong Woon; Kim, Jandi; Park, Seong-Kyu; Kim, Min-Soo; Shin, Kee-Sun; Lee, Jung-Sook; Lee, Keun Chul; Kim, Young-Ok; Bae, Jin-Woo

    2012-12-01

    A slightly halophilic, Gram-negative, strictly aerobic, non-motile rod, designated TW15(T), was isolated from an ark clam in South Korea. Growth occurred at 10-37 °C, with 1-5% (w/v) NaCl and at pH 7.0-10.0. Optimal growth occurred at 25-30 °C, with 2% (w/v) NaCl and at pH 8.0. Strain TW15(T) exhibited both oxidase and catalase activities. The major fatty acids of strain TW15(T) were summed feature 8 (consisting of C(18:1)ω7c and/or C(18:1)ω6c) and 11-methyl C(18:1)ω7c. The predominant isoprenoid quinone was ubiquinone-10 (Q-10). The polar lipids of strain TW15(T) comprised phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, an unidentified phospholipid, an unidentified aminolipid and five unidentified lipids. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain TW15(T) was most closely related to Ruegeria lacuscaerulensis DSM 11314(T) (98.0% 16S rRNA gene sequence similarity). DNA-DNA relatedness with closely related strains was <52 ± 3%. The DNA G+C content was 55.7 mol%. On the basis of phenotypic, genotypic and phylogenetic data, strain TW15(T) represents a novel species of the genus Ruegeria, for which the name Ruegeria conchae sp. nov. is proposed. The type strain is TW15(T) ( = KACC 15115(T)  = JCM 17315(T)).

  5. Temporal dynamics of amino and fatty acid composition in the razor clam Ensis siliqua (Mollusca: Bivalvia)

    Science.gov (United States)

    Baptista, Miguel; Repolho, Tiago; Maulvault, Ana Luísa; Lopes, Vanessa M.; Narciso, Luis; Marques, António; Bandarra, Narcisa; Rosa, Rui

    2014-12-01

    Few studies have been conducted on the temporal dynamics of both amino acid (AA) and fatty acid (FA) profiles in marine bivalves. We investigated the seasonal variation of these compounds in the pod razor clam Ensis siliqua in relation to food availability, salinity, water temperature and reproductive cycle. AA content varied between 46.94 and 54.67 % dry weight (DW), and the AAs found in greater quantity were glutamic acid, glycine and aspartic acid. FA content varied between 34.02 and 87.94 mg g-1 DW and the FAs found in greater quantity were 16:0 and 22:6 n-3. Seasonal trends were observed for AAs and FAs. FAs increased with gametogenesis and decreased with spawning while AA content increased throughout spawning. The effect of increasing temperature and high food availability during the spawning season masked the loss of AAs resulting from gamete release. Still, a comparatively greater increase in the contents of glutamic acid and leucine with spawning indicate their possible involvement in a post-spawning gonad recovery mechanism. A post-spawning decrease in 14:0, 16:0, 16:1 n-7, 18:1 n-7 and 18:1 n-9 is indicative of the importance of these FAs in bivalve eggs. An increase in 18:3 n-3, 18:4 n-3, 20:1 n-9 and 20:2 n-6 during gametogenesis suggests their involvement in oocyte maturation. The FA 22:4 n-6, while increasing with spawning, appears to play a role in post-spawning gonad recovery. Salinity did not have an effect on the AA composition. None of the environmental parameters measured had an effect on FA composition.

  6. Lead and other heavy metals (cadmium and mercury accumulation in bivalve mollusks (Mytilus galloprovincialis, Ruditapes spp. and Crassostrea gigas sampled in Sardinia in 2008-2012

    Directory of Open Access Journals (Sweden)

    Pierluigi Piras

    2013-12-01

    Full Text Available The Sardinian shellfish farming, like the national, is mainly focused on mussels and carpet-shell clams, still less on cupped oyster farming. After Olbia’s Gulf, various lagoon areas along the coastal perimeter have been interested to shellfish farming. They are transitional waters, whose state of pollution must be evaluated both as ecosystem’s health and as directly/indirectly human risk. This also applies to heavy metals such as lead, cadmium and mercury, arising both from anthropogenic that geological-natural activity. The aim of the present study is to investigate the variability of the concentrations of these metals in different mollusks to make a comparative assessment, detect trends (over the five-years or cyclicrecurring and identify hot spots. In 2008- 2012, 984 samples have been analysed by inductively coupled plasma mass spectrometry technique. Of them, 599 in pre-marketing (for classification of production areas or their monitoring and the remaining during marketing. The difference between the average levels of the three metals in the different mollusks species was statistically significant, with Pb>Cd>Hg, and there was evidence of a gradual downward trend, albeit moderate, in the contamination levels, with a significant seasonality in concentrations levels, of lead in particular. Also comparisons between the bio-monitored coastal areas were statistically different. Since the samples were representative of the entire production of bivalve mollusks in Sardinia and the contamination allowable limits have never been exceeded in the products marketed, it can be concluded that these products are safe, pointing out that maintenance of monitoring/surveillance plans provides useful information species-dependent, site-specific and temporal trends.

  7. Identification of Angiotensin I-Converting Enzyme Inhibitory Peptides Derived from Enzymatic Hydrolysates of Razor Clam Sinonovacula constricta

    Directory of Open Access Journals (Sweden)

    Yun Li

    2016-06-01

    Full Text Available Angiotensin I-converting enzyme (ACE inhibitory activity of razor clam hydrolysates produced using five proteases, namely, pepsin, trypsin, alcalase, flavourzyme and proteases from Actinomucor elegans T3 was investigated. Flavourzyme hydrolysate showed the highest level of degree of hydrolysis (DH (45.87% followed by A. elegans T3 proteases hydrolysate (37.84% and alcalase (30.55%. The A. elegans T3 proteases was observed to be more effective in generating small peptides with ACE-inhibitory activity. The 3 kDa membrane permeate of A. elegans T3 proteases hydrolysate showed the highest ACE-inhibitory activity with an IC50 of 0.79 mg/mL. After chromatographic separation by Sephadex G-15 gel filtration and reverse phase-high performance liquid chromatography, the potent fraction was subjected to MALDI/TOF-TOF MS/MS for identification. A novel ACE-inhibitory peptide (VQY was identified exhibiting an IC50 of 9.8 μM. The inhibitory kinetics investigation by Lineweaver-Burk plots demonstrated that the peptide acts as a competitive ACE inhibitor. The razor clam hydrolysate obtained by A. elegans T3 proteases could serve as a source of functional peptides with ACE-inhibitory activity for physiological benefits.

  8. Invasive zebra mussels (Driessena polymorpha) and Asian clams (Corbicula fluminea) survive gut passage of migratory fish species: implications for dispersal

    Science.gov (United States)

    Gatlin, Michael R.; Shoup, Daniel E.; Long, James M.

    2013-01-01

    The introduction and spread of invasive species is of great concern to natural resource managers in the United States. To effectively control the spread of these species, managers must be aware of the multitude of dispersal methods used by the organisms. We investigated the potential for survival through the gut of a migrating fish (blue catfish, Ictalurus furcatus) as a dispersal mechanism for two invasive bivalves: zebra mussel (Driessena polymorpha) and Asian clam (Corbicula fluminea). Blue catfish (N = 62) were sampled over several months from Sooner Lake, Oklahoma, transported to a laboratory and held in individual tanks for 48 h. All fecal material was collected and inspected for live mussels. Survival was significantly related to water temperature in the lake at the time of collection, with no mussels surviving above 21.1 C°, whereas 12 % of zebra mussels (N = 939) and 39 % of Asian clams (N = 408) consumed in cooler water survived gut passage. This research demonstrates the potential for blue catfish to serve as a dispersal vector for invasive bivalves at low water temperatures.

  9. Chemical compositions and nutritional value of Asian hard clam (Meretrix lusoria) from the coast of Andaman Sea.

    Science.gov (United States)

    Karnjanapratum, Supatra; Benjakul, Soottawat; Kishimura, Hideki; Tsai, Yung-Hsiang

    2013-12-15

    Chemical compositions and nutritive value of the edible portions including foot, mantle and viscera of Asian hard clam (Meretrix lusoria) harvested from the coast of Andaman Sea were determined. Proximate compositions varied with portions tested. Edible portions had moisture (76.23-84.22%) and protein (9.09-12.75%) as the major components. Carbohydrate (0.32-7.89%), fat (1.58-6.58%) and ash (1.23-2.58%) were also found at various levels, dependent upon portions. Myofibrillar proteins were observed as the major fraction in foot (40.54%) and mantle (31.65%), whilst non-protein nitrogen constituents were dominant in the viscera (36.85%). All portions contained a large amount of essential amino acids (167.66-187.63 mg/g sample), in which leucine (30.91-36.96 mg/g sample) and lysine (35.24-36.03 mg/g sample) were predominant. They were rich in polyunsaturated fatty acids (46.84-49.18% of total fatty acid) with high level of DHA (13.33-16.47 % of total fatty acids) and EPA (4.75-7.11% of total fatty acids). Cholesterol of 0.07-0.21% wet weight was detected. All portions were also rich in macro- (Na, K, Ca and Mg) and micro- (Fe, Zn, Cu and Cr) minerals. Therefore, Asian hard clam is an excellent source of several nutrients, which could be beneficial for the health of the consumers.

  10. Effects of LSP on micro-structures and residual stresses in a 4 mm CLAM steel weld joints

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xizhang, E-mail: chenxizhang@wzu.edu.cn [School of Mechanical and Electrical Engineering, Wenzhou University., Wenzhou 325035 (China); School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu (China); Fang, Yuanyuan [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu (China); Zhang, Shuyan; Kelleher, Joe F. [ISIS, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX (United Kingdom); Zhou, Jianzhong [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu (China)

    2015-05-15

    The effects of laser shock processing (LSP) on the distribution of residual stress and micro-structure of China Low Activation Martensitic (CLAM) steel weldment were investigated via neutron diffraction and optical microscope (OM). A pair of 4 mm CLAM steel plates joined by GTA welding. Special attention is paid to the generation of high level compressive residual stresses introduced by LSP. Residual stress in longitudinal, normal and transversal direction at weldment surface and longitudinal stress through thickness are evaluated via neutron diffraction. Compressive residual stress after LSP occurred at more than 90% areas within the weld joint, it is almost double the areas of compressive stress compare to weldment surface before LSP. The maximum compressive normal residual stress becomes to −183 MPa after LSP from −63 MPa before LSP. The Modification of surface micro-structures including weld zone (WZ), heat affected zone (HAZ) and base metal (BM) are also discussed. Results to date demonstrate that laser shock processing has been a great potential method for the improvement of mechanical performance of components.

  11. Cryptic species of deep-sea clams (Mollusca: Bivalvia: Vesicomyidae) from hydrothermal vent and cold-water seep environments

    Science.gov (United States)

    Vrijenhoek, Robert C.; Schutz, Steven J.; Gustafson, Richard G.; Lutz, Richard A.

    1994-08-01

    A protein-electrophoretic analysis of six putative morphospecies in the bivalve family Vesicomyidae from eight deep-sea hydrothermal vent sites in the eastern Pacific, three cold-water seep sites in the eastern Pacific and the Gulf of Mexico, and one whale-carcass site off Southern California revealed electromorph patterns diagnostic of 10 vesicomyid species. Electrophoretic patterns for 14 enzymes encoded by 17 presumptive gene loci were scored in all 10 species. The pairwise genetic distances (Nei's D) for these 10 species ranged from 0.857 to 2.792, values within the range expected for distinct species and genera. However, the degree of genetic divergence among these taxa could not be used for phylogenetic inferences because allozyme differences had in many cases reached evolutionary saturation. Notwithstanding, the present results revealed a significant problem with current morphospecies identifications of these clams and with applications of the current generic names Calyptogena and Vesicomya. Given the cryptic nature of these taxa, we suggest that subsequent studies simply refer to these clams as "vesicomyids" until careful morphological analyses and molecular studies are completed and systematic relationships are clarified.

  12. Identification of a regulation network in response to cadmium toxicity using blood clam Tegillarca granosa as model

    Science.gov (United States)

    Bao, Yongbo; Liu, Xiao; Zhang, Weiwei; Cao, Jianping; Li, Wei; Li, Chenghua; Lin, Zhihua

    2016-01-01

    Clam, a filter-feeding lamellibranch mollusk, is capable to accumulate high levels of trace metals and has therefore become a model for investigation the mechanism of heavy metal toxification. In this study, the effects of cadmium were characterized in the gills of Tegillarca granosa during a 96-hour exposure course using integrated metabolomic and proteomic approaches. Neurotoxicity and disturbances in energy metabolism were implicated according to the metabolic responses after Cd exposure, and eventually affected the osmotic function of gill tissue. Proteomic analysis showed that oxidative stress, calcium-binding and sulfur-compound metabolism proteins were key factors responding to Cd challenge. A knowledge-based network regulation model was constructed with both metabolic and proteomic data. The model suggests that Cd stimulation mainly inhibits a core regulation network that is associated with histone function, ribosome processing and tight junctions, with the hub proteins actin, gamma 1 and Calmodulin 1. Moreover, myosin complex inhibition causes abnormal tight junctions and is linked to the irregular synthesis of amino acids. For the first time, this study provides insight into the proteomic and metabolomic changes caused by Cd in the blood clam T. granosa and suggests a potential toxicological pathway for Cd. PMID:27760991

  13. Cypermethrin-Induced Toxic Effect on Glycogen Metabolism in Estuarine Clam, Marcia Opima (Gmelin, 1791 of Ratnagiri Coast, Maharashtra

    Directory of Open Access Journals (Sweden)

    Medha Tendulkar

    2012-01-01

    Full Text Available Cypermethrin is a synthetic pyrethroid class of insecticide. Toxic effects of cypermethrin were studied by selecting Marcia opima as an animal model. Cypermethrins effect on the total glycogen content of mantle, gill, foot, hepatopancreas, male gonad and a female gonad of an estuarine clam, Marcia opima was examined. The clams were exposed to 1.58 ppm cypermethrin for acute and 1/th of that concentration for chronic treatment. It was found that there was a decrease in glycogen content in various tissues as compared to control. In LC0 and LC50 groups, glycogen was decreased in all tissues except in hepatopancreas compared to control. This decrease is greater in mantle, gill, and foot in LC50 group than the decrease in those tissues of LC0 group. In chronic exposure it was found that glycogen was decreased in mantle, foot, male gonad, and female gonad when compared to the control group except in gill and hepatopancreas. Decrease in glycogen content indicates greater utilization of glycogen for metabolic purposes and too combat with cypermethrin stress. The significant increase in glycogen content in gill and hepatopancreas may be a reaction to the increase in energy demand.

  14. Heterogeneity of macrozoobenthic assemblages within a Zostera noltii seagrass bed: diversity, abundance, biomass and structuring factors

    Science.gov (United States)

    Blanchet, Hugues; de Montaudouin, Xavier; Lucas, Aurélien; Chardy, Pierre

    2004-09-01

    complete replacement of the native clam Ruditapes decussatus by the Manila clam Ruditapes philippinarum since its introduction in the 1980s.

  15. Variation in heavy metals concentration in the edible oyster Crassostrea madrasensis, clam Polymesoda erosa and grey mullet Liza aurata from coastline of India

    Digital Repository Service at National Institute of Oceanography (India)

    Gawade, L.; Chari, N.V.H.; Sarma, V.V.; Ingole, B.S.

    and to the other markets. Whereas the clam polymesoda erosa is very common in markets and is of public interest. 2.2. Methodology Analyses were carried out using 18 fish samples with size varying from 8-16 cm total length and 18 oyster samples of size varying from...

  16. Tropomyosin and Actin Identified as Major Allergens of the Carpet Clam (Paphia textile and the Effect of Cooking on Their Allergenicity

    Directory of Open Access Journals (Sweden)

    Zailatul Hani Mohamad Yadzir

    2015-01-01

    Full Text Available Objectives. To identify the major allergenic proteins of clam (Paphia textile and to investigate the effect of different cooking methods on the allergenicity of these identified proteins. Methods. Clam protein extracts were separated by denaturing polyacrylamide gel electrophoresis. IgE reactive proteins were then analyzed by immunoblotting with sera from patients with positive skin prick tests (SPT to the raw clam extract. Mass spectrometry was used to identify the major allergenic proteins of this clam. Results. Raw extract showed 12 protein bands (18–150 kDa. In contrast, fewer protein bands were seen in the boiled extract; those ranging from 40 to 150 kDa were denatured. The protein profiles were similarly altered by frying or roasting. The immunoblots of raw and boiled extracts yielded 10 and 2 IgE-binding proteins, respectively. The fried and roasted extracts showed only a single IgE-binding protein at 37 kDa. Mass spectrometry analysis of the 37 and 42 kDa major allergens indicated that these spots were tropomyosin and actin, respectively. Conclusion. The two major allergens of Paphia textile were identified as the thermostable tropomyosin and a new thermolabile allergen actin.

  17. Seasonal changes in physiological responses and evaluation of "well-being" in the Venus clam Chamelea gallina from the Northern Adriatic Sea.

    Science.gov (United States)

    Moschino, Vanessa; Marin, Maria Gabriella

    2006-12-01

    Chamelea gallina is an infaunal bivalve, widespread in sandy bottoms along Mediterranean coasts. It is an important economic resource for fisheries in the Adriatic, although in recent years over-fishing, and other concurrent factors, have dramatically decreased clam harvesting. In this context, it is of great interest to gain information on seasonal variations in the physiological performance of clams, for an overall evaluation of their well-being. In this study, laboratory experiments were performed to define allometric relationships and effects of temperature on clearance and respiration rates of C. gallina. The mean values of b coefficients were calculated and used to correlate physiological measurements to 'standard' body mass, when seasonally collected clams were analysed. The highest clearance rate (0.42 L h(-1)) was measured in clams collected in July 2000; the highest respiration rate (12.22 micromol O2 h(-1)) was observed in July 2001, leading to a negative scope for growth (-2.8 J h(-1)). The influence of environmental and endogenous factors, mostly reproduction, was discussed. Survival in air and condition indices, showing higher stress conditions in December 2000 and July 2001, were in good agreement with the other physiological measurements. The physiological responses examined in this study appear to be suitable for providing detailed indications on the well-being of C. gallina and may be useful for future studies aimed at eco-sustainable management of the resource.

  18. Contrasting Physiological Responses of Two Populations of the Razor Clam Tagelus dombeii with Different Histories of Exposure to Paralytic Shellfish Poisoning (PSP)

    Science.gov (United States)

    Navarro, Jorge M.; González, Katerina; Cisternas, Barbara; López, Jorge A.; Chaparro, Oscar R.; Segura, Cristian J.; Córdova, Marco; Suárez-Isla, Benjamín; Fernandez-Reiriz, María J.; Labarta, Uxio

    2014-01-01

    This study describes the physiological performance of two populations of the razor clam Tagelus dombeii from two geographic areas with different histories of exposure to paralytic shellfish poisoning (PSP) linked to the toxic dinoflagellate Alexandrium catenella. Clams from Melinka-Aysén, which are frequently exposed to PSP, were not affected by the presence of toxins in the diet. However, clams from Corral-Valdivia, which have never been exposed to PSP, exhibited significantly reduced filtration activity and absorption, affecting the energy allocated to scope for growth (SFG). Ammonia excretion and oxygen uptake were not affected significantly by the presence of A. catenella in the diet. Measurements of energy acquisition and expenditure were performed during a 12-day intoxication period. According to three-way repeated measure ANOVAs, the origin of the clams had a highly significant effect on all physiological variables, and the interaction between diet and origin was significant for the clearance and absorption rates and for the scope for growth. The scope for growth index showed similar positive values for both the toxic and non-toxic individuals from the Melinka-Aysén population. However, it was significantly reduced in individuals from Corral-Valdivia when exposed to the diet containing A. catenella. The absence of differences between the physiological response of the toxic and non-toxic clams from Melinka-Aysén may be related to the frequent presence of A. catenella in the environment, indicating that this bivalve does not suffer negative consequences from PSP. By contrast, A. catenella has a negative effect on the physiological performance, primarily on the energy gained from the environment, on T. dombeii from Corral-Valdivia. This study supports the hypothesis that the history of PSP exposure plays an important role in the physiological performance and fitness of filter feeding bivalves. PMID:25153329

  19. Contrasting physiological responses of two populations of the razor clam Tagelus dombeii with different histories of exposure to paralytic shellfish poisoning (PSP).

    Science.gov (United States)

    Navarro, Jorge M; González, Katerina; Cisternas, Barbara; López, Jorge A; Chaparro, Oscar R; Segura, Cristian J; Córdova, Marco; Suárez-Isla, Benjamín; Fernandez-Reiriz, María J; Labarta, Uxio

    2014-01-01

    This study describes the physiological performance of two populations of the razor clam Tagelus dombeii from two geographic areas with different histories of exposure to paralytic shellfish poisoning (PSP) linked to the toxic dinoflagellate Alexandrium catenella. Clams from Melinka-Aysén, which are frequently exposed to PSP, were not affected by the presence of toxins in the diet. However, clams from Corral-Valdivia, which have never been exposed to PSP, exhibited significantly reduced filtration activity and absorption, affecting the energy allocated to scope for growth (SFG). Ammonia excretion and oxygen uptake were not affected significantly by the presence of A. catenella in the diet. Measurements of energy acquisition and expenditure were performed during a 12-day intoxication period. According to three-way repeated measure ANOVAs, the origin of the clams had a highly significant effect on all physiological variables, and the interaction between diet and origin was significant for the clearance and absorption rates and for the scope for growth. The scope for growth index showed similar positive values for both the toxic and non-toxic individuals from the Melinka-Aysén population. However, it was significantly reduced in individuals from Corral-Valdivia when exposed to the diet containing A. catenella. The absence of differences between the physiological response of the toxic and non-toxic clams from Melinka-Aysén may be related to the frequent presence of A. catenella in the environment, indicating that this bivalve does not suffer negative consequences from PSP. By contrast, A. catenella has a negative effect on the physiological performance, primarily on the energy gained from the environment, on T. dombeii from Corral-Valdivia. This study supports the hypothesis that the history of PSP exposure plays an important role in the physiological performance and fitness of filter feeding bivalves.

  20. Interactive effects of mosquito control insecticide toxicity, hypoxia, and increased carbon dioxide on larval and juvenile eastern oysters and hard clams.

    Science.gov (United States)

    Garcia, R N; Chung, K W; Key, P B; Burnett, L E; Coen, L D; Delorenzo, M E

    2014-04-01

    Mosquito control insecticide use in the coastal zone coincides with the habitat and mariculture operations of commercially and ecologically important shellfish species. Few data are available regarding insecticide toxicity to shellfish early life stages, and potential interactions with abiotic stressors, such as low oxygen and increased CO2 (low pH), are less understood. Toxicity was assessed at 4 and 21 days for larval and juvenile stages of the Eastern oyster, Crassostrea virginica, and the hard clam, Mercenaria mercenaria, using two pyrethroids (resmethrin and permethrin), an organophosphate (naled), and a juvenile growth hormone mimic (methoprene). Acute toxicity (4-day LC50) values ranged from 1.59 to >10 mg/L. Overall, clams were more susceptible to mosquito control insecticides than oysters. Naled was the most toxic compound in oyster larvae, whereas resmethrin was the most toxic compound in clam larvae. Mortality for both species generally increased with chronic insecticide exposure (21-day LC50 values ranged from 0.60 to 9.49 mg/L). Insecticide exposure also caused sublethal effects, including decreased swimming activity after 4 days in larval oysters (4-day EC50 values of 0.60 to 2.33 mg/L) and decreased growth (shell area and weight) in juvenile clams and oysters after 21 days (detected at concentrations ranging from 0.625 to 10 mg/L). Hypoxia, hypercapnia, and a combination of hypoxia and hypercapnia caused mortality in larval clams and increased resmethrin toxicity. These data will benefit both shellfish mariculture operations and environmental resource agencies as they manage the use of mosquito control insecticides near coastal ecosystems.

  1. Characterisation of 12 microsatellite loci in the Vietnamese commercial clam Lutraria rhynchaena Jonas 1844 (Heterodonta: Bivalvia: Mactridae) through next-generation sequencing.

    Science.gov (United States)

    Thai, Binh Thanh; Tan, Mun Hua; Lee, Yin Peng; Gan, Han Ming; Tran, Trang Thi; Austin, Christopher M

    2016-05-01

    The marine clam Lutraria rhynchaena is gaining popularity as an aquaculture species in Asia. Lutraria populations are present in the wild throughout Vietnam and several stocks have been established and translocated for breeding and aquaculture grow-out purposes. In this study, we demonstrate the feasibility of utilising Illumina next-generation sequencing technology to streamline the identification and genotyping of microsatellite loci from this clam species. Based on an initial partial genome scan, 48 microsatellite markers with similar melting temperatures were identified and characterised. The 12 most suitable polymorphic loci were then genotyped using 51 individuals from a population in Quang Ninh Province, North Vietnam. Genetic variation was low (mean number of alleles per locus = 2.6; mean expected heterozygosity = 0.41). Two loci showed significant deviation from Hardy-Weinberg equilibrium (HWE) and the presence of null alleles, but there was no evidence of linkage disequilibrium among loci. Three additional populations were screened (n = 7-36) to test the geographic utility of the 12 loci, which revealed 100 % successful genotyping in two populations from central Vietnam (Nha Trang). However, a second population from north Vietnam (Co To) could not be successfully genotyped and morphological evidence and mitochondrial variation suggests that this population represents a cryptic species of Lutraria. Comparisons of the Qang Ninh and Nha Trang populations, excluding the 2 loci out of HWE, revealed statistically significant allelic variation at 4 loci. We reported the first microsatellite loci set for the marine clam Lutraria rhynchaena and demonstrated its potential in differentiating clam populations. Additionally, a cryptic species population of Lutraria rhynchaena was identified during initial loci development, underscoring the overlooked diversity of marine clam species in Vietnam and the need to genetically characterise population representatives prior

  2. 体积排阻高效液相色谱-电感耦合等离子体质谱法测定海产贝类中镉的形态%Speciation Analysis of Cadmium in Marine Bivalves by Size Exclusion Chromatography-High Performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    赵艳芳; 尚德荣; 宁劲松; 翟毓秀

    2012-01-01

    The speciation analysis of cadmium in the scallop (Chlamys farreri, C. farreri) with high Cd accumulation capability and the clam (Ruditapes philippinarum, R. philippivarum) with low Cd accumulation capability was first conducted by size exclusion chromatography-high performance liquid chromatography-inductivcly coupled plasma mass spectrometry (SEC-HPLC-ICP-MS), and in vitro whole-bionic digestion model was used to determine the cadmium speciation in two bivalves under the action of saliva, the acidity of stomach and intestine with inorganic and organic components and diges-tion enzymes. The results showed that the total cadmium content in C. farreri was almost 10 times in R. philippinarum. Three Cd species, metallothionein (MT)-Cd, glutathione (GSH)-Cd and cystein (Cys)-Cd were detected in C. farreri, and two Cd species, MT-Cd and GSH-Cd were detected in R. philippinarum. According to the different peak areas, MT-Cd and GSH-Cd content in C. farreri was about 5. 6 and 2. 0 times of those in R. philippinarum respectively. Using in vitro whole-bionic diges-tion model, one unknown Cd species with small molecule (named Cd-X) was detected in whole-bionic digestion of gastric extracts, and four Cd species (mainly MT-Cd) were detected in the whole-bionic digestion of intestine extracts for C. farreri; however, for R. philippinarum, the unknown Cd-X was the main Cd species in both gastric and intestinal extracts. The experiment also proves that Cd can be separated from MT-Cd, GSH-Cd and Cys-Cd under the effect of the whole-bionic digestion of stomach and intestine.%运用体积排阻高效液相色谱-电感耦合等离子体质谱联用技术(SEC-HPLC-ICP-MS)分析了高镉积累扇贝和低镉积累菲律宾蛤仔中镉的存在形态,并结合体外全仿生消化技术,研究了在唾液、胃、肠无机物和有机物(含消化酶)作用下,扇贝和菲律宾蛤仔中镉的主要存在形态.结果发现:扇贝中Cd总量约为菲律宾蛤仔的10

  3. Persistent organic pollutants (POPs) in populations of the clam Chione californiensis in coastal lagoons of the Gulf of California.

    Science.gov (United States)

    Vargas-González, Héctor H; Méndez-Rodríguez, Lía C; García-Hernández, Jaqueline; Mendoza-Salgado, Renato A; Zenteno-Savín, Tania; Arreola-Lizárraga, José A

    2016-07-02

    This study examines the potential public health risk due to the massive use of organochlorine pesticides (OCs) in agriculture in the Gulf of California. Specimens of the clam Chione californiensis were collected from three coastal lagoons (Yavaros, Altata and Reforma). Sites were classified as polluted/nonpolluted based on the presence/absence of OCs as an indicator of the persistence of these pollutants; in polluted sites, the time elapsed since pesticide application (past or recent) was estimated. Screening values (SV) for protecting human health as per the U.S. Environmental Protection Agency (EPA) were used for risk assessment. OCs detected were ranked according to frequency of occurrence as follows: γ-chlordane (75%) > endrin (54%) > aldrin (48%) > heptachlor, and dichlorodiphenyl-trichloroethane (DDE) (37%) > β-heptachlor epoxide (30%) > lindane (α-BHC, δ-BHC) and endosulphan I (≤ 6%). Specifically, OCs detected at the highest concentration were heptachlor in Yavaros (0.0168 µgg(-1)) and Altata (0.0046 µgg(-1)), and aldrin in Reforma (0.0019 µgg(-1)). β-Heptachlor epoxide in Altata and Reforma was the only OC with a concentration exceeding the EPA Screening Value. From our results and based on the monthly consumption limit set forth by EPA, the maximum safe consumption of clams to avoid a carcinogenic risk derived from β-heptachlor epoxide in the fishing villages of Yavaros and Altata is 4 servings per month (1 serving = 0.227 kg) by a 70-kg person. These findings suggest that concentrations of OCs and their isomers in C. californiensis populations reflect environmental persistence as well as recent inputs of OCs into coastal lagoons in the Gulf of California.

  4. Metals bioaccumulation and biomarkers responses in the Neotropical freshwater clam Anodontites trapesialis: Implications for monitoring coal mining areas.

    Science.gov (United States)

    Oliveira, Luciana Fernandes de; Cabral, Millena Terezinha; Vieira, Carlos Eduardo Delfino; Antoniazzi, Matheus Henrique; Risso, Wagner Ezequiel; Martinez, Claudia Bueno Dos Reis

    2016-11-15

    As one of the most impactful industries, coal mining can promote several alterations at surrounding environment. In surface water, elevated concentrations of metals like Mn, Zn, Fe and Al are often observed. Thus, the aim of this study was to investigate the bioaccumulation and the sub-lethal effects of these metals on various organs of the Neotropical bivalve Anodontites trapesialis confined along a stream located near a coal mine, in order to assess a set of biomarkers that could be used for effectively monitoring coal mining areas. Clams were caged, for 96h, at two sites located upstream (Up1 and Up2) and two sites downstream (Dw1 and Dw2) from the mine. Metals bioaccumulation was determined in gills, mantle, digestive gland, muscle and hemolymph and the following biomarkers were measured in A. trapesialis tissues: total antioxidant capacity against peroxyl radicals, metallothionein content, lipid peroxidation (LPO), proteins carbonylation, glutathione S-transferase activity, superoxide dismutase activity and acetylcholinesterase (AChE) activity. The results showed that Al and Fe bioaccumulation in the gills and hemolymph, Al bioaccumulation in the mantle and muscle, increased LPO in the gills (Dw1 and Dw2) and mantle (Dw1), as well as reduced AChE activity in the muscle (Dw1 and Dw2) should be considered effective biomarkers for monitoring coal mining areas. A. trapesialis proved to be an efficient biological model, considering that biomarkers responses were observed in the clams after only 96h of confinement at Dw sites, accordingly this species could be a good candidate for monitoring Neotropical freshwaters.

  5. Toxicological responses of the hard clam Meretrix meretrix exposed to excess dissolved iron or challenged by Vibrio parahaemolyticus

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Qing [State Key Laboratory of Stress Cell Biology, School of Life Science, Xiamen University, Xiamen 361102 (China); State Key Laboratory of Marine Environmental Science, School of Ocean and Earth Science, Xiamen University, Xiamen 361102 (China); Zhang, Yong [Department of Chemistry, College of Chemistry and Chemical Engineering, and the Key Laboratory of Chemical Biology of Fujian Province, Xiamen University, Xiamen 361102 (China); Peng, Hui-Fang [State Key Laboratory of Stress Cell Biology, School of Life Science, Xiamen University, Xiamen 361102 (China); Ke, Cai-Huan, E-mail: chke@xmu.edu.cn [State Key Laboratory of Marine Environmental Science, School of Ocean and Earth Science, Xiamen University, Xiamen 361102 (China); Huang, He-Qing, E-mail: hqhuang@xmu.edu.cn [State Key Laboratory of Stress Cell Biology, School of Life Science, Xiamen University, Xiamen 361102 (China); State Key Laboratory of Marine Environmental Science, School of Ocean and Earth Science, Xiamen University, Xiamen 361102 (China); Department of Chemistry, College of Chemistry and Chemical Engineering, and the Key Laboratory of Chemical Biology of Fujian Province, Xiamen University, Xiamen 361102 (China)

    2014-11-15

    Highlights: • Fe accumulated in hepatopancreas tissues after iron-enriched exposure. • Ferritin expression was positively correlated with iron concentration in seawater. • Ferritin appears to be involved in iron homeostasis and immune defense mechanism of M. meretrix. • mRNAs of cytokine genes responded faster than antioxidant enzyme genes in immune defense mechanism. • The study gives a new potential biomarker for monitoring iron levels in seawater. - Abstract: The responses of genes encoding defense components such as ferritin, the lipopolysaccharide-induced tumor necrosis factor-alpha factor (LITAF), the inhibitor of nuclear factor-κB (IκB), metallothionein, and glutathione peroxidase were assessed at the transcriptional level in order to investigate the toxicological and immune mechanism of the hard clam Meretrix meretrix (HCMM) following challenge with iron or a bacterium (Vibrio parahaemolyticus). Fe dissolved in natural seawater led to an increase of Fe content in both the hepatopancreas and gill tissue of HCMM between 4 and 15 days of exposure. The ferritin gene responded both transcriptionally as indicated by real-time quantitative PCR and translationally as shown by western blotting results to iron exposure and both transcriptional and translational ferritin expression in the hepatopancreas had a positive correlation with the concentration of dissolved iron in seawater. Both iron and V. parahaemolyticus exposure triggered immune responses with similar trends in clam tissues. There was a significant post-challenge mRNA expression of LITAF and IκB at 3 h, ferritin at 24 h, and metallothionein and glutathione peroxidase at 48 h. This behavior might be linked to their specific functions in physiological processes. These results suggested that similar signaling pathways were triggered during both iron and V. parahaemolyticus challenges. Here, we indicated that the ferritin of Meretrix meretrix was an intermediate in the pathway of iron homeostasis

  6. Sequencing and de novo assembly of the Asian clam (Corbicula fluminea transcriptome using the Illumina GAIIx method.

    Directory of Open Access Journals (Sweden)

    Huihui Chen

    Full Text Available BACKGROUND: The Asian clam (Corbicula fluminea is currently one of the most economically important aquatic species in China and has been used as a test organism in many environmental studies. However, the lack of genomic resources, such as sequenced genome, expressed sequence tags (ESTs and transcriptome sequences has hindered the research on C. fluminea. Recent advances in large-scale RNA-Seq enable generation of genomic resources in a short time, and provide large expression datasets for functional genomic analysis. METHODOLOGY/PRINCIPAL FINDINGS: We used a next-generation high-throughput DNA sequencing technique with an Illumina GAIIx method to analyze the transcriptome from the whole bodies of C. fluminea. More than 62,250,336 high-quality reads were generated based on the raw data, and 134,684 unigenes with a mean length of 791 bp were assembled using the Velvet and Oases software. All of the assembly unigenes were annotated by running BLASTx and BLASTn similarity searches on the Nt, Nr, Swiss-Prot, COG and KEGG databases. In addition, the Clusters of Orthologous Groups (COGs, Gene Ontology (GO terms and Kyoto Encyclopedia of Gene and Genome (KEGG annotations were also assigned to each unigene transcript. To provide a preliminary verification of the assembly and annotation results, and search for potential environmental pollution biomarkers, 15 functional genes (five antioxidase genes, two cytochrome P450 genes, three GABA receptor-related genes and five heat shock protein genes were cloned and identified. Expressions of the 15 selected genes following fluoxetine exposure confirmed that the genes are indeed linked to environmental stress. CONCLUSIONS/SIGNIFICANCE: The C. fluminea transcriptome advances the underlying molecular understanding of this freshwater clam, provides a basis for further exploration of C. fluminea as an environmental test organism and promotes further studies on other bivalve organisms.

  7. Exclusive localization of carbonic anhydrase in bacteriocytes of the deep-sea clam Calyptogena okutanii with thioautotrophic symbiotic bacteria.

    Science.gov (United States)

    Hongo, Yuki; Nakamura, Yoshimitsu; Shimamura, Shigeru; Takaki, Yoshihiro; Uematsu, Katsuyuki; Toyofuku, Takashi; Hirayama, Hisako; Takai, Ken; Nakazawa, Masatoshi; Maruyama, Tadashi; Yoshida, Takao

    2013-12-01

    Deep-sea Calyptogena clams harbor thioautotrophic intracellular symbiotic bacteria in their gill epithelial cells. The symbiont fixes CO2 to synthesize organic compounds. Carbonic anhydrase (CA) from the host catalyzes the reaction CO2 + H2O ↔ HCO3(-) + H(+), and is assumed to facilitate inorganic carbon (Ci) uptake and transport to the symbiont. However, the localization of CA in gill tissue remains unknown. We therefore analyzed mRNA sequences, proteins and CA activity in Calyptogena okutanii using expression sequence tag, SDS-PAGE and LC-MS/MS. We found that acetazolamide-sensitive soluble CA was abundantly expressed in the gill tissue of C. okutanii, and the enzyme was purified by affinity chromatography. Mouse monoclonal antibodies against the CA of C. okutanii were used in western blot analysis and immunofluorescence staining of the gill tissues of C. okutanii, which showed that CA was exclusively localized in the symbiont-harboring cells (bacteriocytes) in gill epithelial cells. Western blot analysis and measurement of activity showed that CA was abundantly (26-72% of total soluble protein) detected in the gill tissues of not only Calyptogena clams but also deep-sea Bathymodiolus mussels that harbor thioautotrophic or methanotrophic symbiotic bacteria, but was not detected in a non-symbiotic mussel, Mytilus sp. The present study showed that CA is abundant in the gill tissues of deep-sea symbiotic bivalves and specifically localizes in the cytoplasm of bacteriocytes of C. okutanii. This indicates that the Ci supply process to symbionts in the vacuole (symbiosome) in bacteriocytes is essential for symbiosis.

  8. Update of information on perkinsosis in NW Mediterranean coast: Identification of Perkinsus spp. (Protista) in new locations and hosts.

    Science.gov (United States)

    Ramilo, Andrea; Carrasco, Noelia; Reece, Kimberly S; Valencia, José M; Grau, Amalia; Aceituno, Patricia; Rojas, Mauricio; Gairin, Ignasi; Furones, M Dolores; Abollo, Elvira; Villalba, Antonio

    2015-02-01

    This study addressed perkinsosis in commercially important mollusc species in the western Mediterranean area. Perkinsus olseni was found in Santa Gilla Lagoon (Sardinia) infecting Ruditapes decussatus, Cerastoderma glaucum and Venerupis aurea, in Balearic Islands infecting Venus verrucosa and in Delta de l'Ebre (NE Spain) parasitising Ruditapes philippinarum and R. decussatus. Perkinsus mediterraneus was detected infecting Ostrea edulis from the Gulf of Manfredonia (SE Italy) and Alacant (E Spain), V. verrucosa and Arca noae from Balearic Islands and Chlamys varia from Balearic Islands, Alacant and Delta de l'Ebre.

  9. Mating behaviour in laevicaudatan clam shrimp (Crustacea, Branchiopoda and functional morphology of male claspers in a phylogenetic context: a video-based analysis.

    Directory of Open Access Journals (Sweden)

    Zandra M S Sigvardt

    Full Text Available Clam shrimps are freshwater branchiopod crustaceans which often present complicated breeding systems including asexual reproduction (parthenogenesis and mixed mating systems (in androdioecious species both selfing and outcrossing occurs due to the co-presence of hermaphrodites and males. Reproductive patterns of Spinicaudata, which contains most clam shrimp species, have received much attention. Another group of clam shrimps, Laevicaudata, which holds a key position in branchiopod phylogeny, has practically not been studied. As a part of the mating process, males clasp to the carapace margin of the females with a pair (or two pairs of anterior trunk limbs modified as claspers. Previous studies have shown that clasper morphology is important in a phylogenetic context, and that some parts of the claspers in Spinicaudata and Laevicaudata may have undergone a remarkable parallel evolution. Here we have used video microscopy to study aspects of the mating behaviour, egg extrusion, and fertilization in Lynceus brachyurus (Laevicaudata. It is shown that fertilization is likely to be external and that the peculiar tri-lobed lateral lamellae of female's hind body assist in guiding the egg mass to the exopodal egg carriers where they are collected by their distal setation. The functional morphology of the male claspers was studied in detail by close-up video recordings. The movable "finger" of the clasper bends around the female's carapace edge and serves to hold the female during mating. The larger palp grasps around the female carapace margin in a way very similar to the movable "finger", possibly indirectly providing sensory input on the "finger" position. A brief comparative study of the claspers of a spinicaudatan clam shrimp showed both similarities and differences to the laevicaudatan claspers. The presence of two pairs of claspers in Spinicaudata seems to give males a better hold of the female which may play a role during extended mate guarding.

  10. Benthic community structure and biomarker responses of the clam Scrobicularia plana in a shallow tidal creek affected by fish farm effluents (Rio San Pedro, SW Spain).

    Science.gov (United States)

    Silva, Claudio; Mattioli, Mattia; Fabbri, Elena; Yáñez, Eleuterio; Delvalls, T Angel; Martín-Díaz, M Laura

    2012-10-15

    The effects of solid organic wastes from a marine fish farm on sediments were tested using benthic community as ecological indicators and biomarkers in native clam (Scrobicularia plana) as biochemical indicators. The benthic fauna and clam samples were collected in the intertidal sediment in October 2010 from five sites of the Rio San Pedro (RSP) creek, following a gradient of contamination from the aquaculture effluent to the control site. Numbers of species, abundance, richness and Shannon diversity were the biodiversity indicators measured in benthic fauna. Morphological and reproduction status of clams were assessed using the condition factor and gonado-somatic index, respectively. Phase I and Phase II detoxification enzymatic activities (ethoxyresorufin O-deethylase (EROD), glutathione S-transferase (GST)), antioxidant enzymatic activities (glutathione peroxidase (GPX), glutathione reductase (GR)) and oxidative stress parameters (Lipid Peroxidation (LPO) and DNA strand breaks) were measured in clams' digestive gland tissues. In parallel, temperature and salinity in the adjacent water, redox potential, pH and organic matter in sediment, and dissolved oxygen in the interstitial water were measured. The results suggested that RSP showed a spatial gradient characterised by hypoxia/anoxia, reduced potential, acidic conditions and high organic enrichment in sediments at the most contaminated sites. Significant (pbiodiversity indicators were observed in the areas impacted by the aquaculture discharges. Biomarkers did not show a clear pattern and of all biochemical responses tested, GPX, DNA damage and LPO were the most sensitive ones and showed significant (ppolluted sites. Benthic biodiversity indicators were significantly (pchanges of the benthic population structure and health status of the exposed organisms.

  11. Freshwater Clam Extract Ameliorates Triglyceride and Cholesterol Metabolism through the Expression of Genes Involved in Hepatic Lipogenesis and Cholesterol Degradation in Rats

    Directory of Open Access Journals (Sweden)

    Thomas Laurent

    2013-01-01

    Full Text Available The freshwater clam (Corbicula spp. is a popular edible bivalve and has been used as a folk remedy for liver disease in Asia. As a Chinese traditional medicine, it is said that freshwater clam ameliorates alcoholic intoxication and cholestasis. In this study, to estimate the practical benefit of freshwater clam extract (FCE, we compared the effects of FCE and soy protein isolate (SPI on triglyceride and cholesterol metabolism in rats. FCE and SPI lowered serum cholesterol, and FCE tended to reduce serum triglycerides. FCE enhanced fecal sterol excretion and hepatic mRNA levels of CYP7A1 and ABCG5 more substantially than SPI; however, both diets reduced hepatic cholesterol. Both of the diets similarly suppressed liver lipids improved Δ9-desaturated fatty acid profile, and FCE was associated with a reduction in FAS and SCD1 mRNA levels. Hepatic transcriptome analysis revealed that inhibition of lipogenesis-related gene expression may contribute to downregulation of hepatic triglycerides by FCE. FCE would have better potential benefits for preventing metabolic disorders, through greater improvement of metabolism of triglycerides and cholesterol, likely through a mechanism similar to SPI.

  12. Large-scale mitochondrial COI gene sequence variability reflects the complex colonization history of the invasive soft-shell clam, Mya arenaria (L.) (Bivalvia)

    Science.gov (United States)

    Lasota, Rafal; Pierscieniak, Karolina; Garcia, Pascale; Simon-Bouhet, Benoit; Wolowicz, Maciej

    2016-11-01

    The aim of the study was to determine genetic diversity in the soft-shell clam Mya arenaria on a wide geographical scale using mtDNA COI gene sequences. Low levels of genetic diversity was found, which can most likely be explained by a bottleneck effect during Pleistocene glaciations and/or selection. The geographical genetic structuring of the studied populations was also very low. The star-like phylogeny of the haplotypes indicates a relatively recent, rapid population expansion following the glaciation period and repeated expansion following the founder effect(s) after the initial introduction of the soft-shell clam to Europe. North American populations are characterized by the largest number of haplotypes, including rare ones, as expected for native populations. Because of the founder effect connected with initial and repeated expansion events, European populations have significantly lower numbers of haplotypes in comparison with those of North America. We also observed subtle differentiations among populations from the North and Baltic seas. The recently founded soft-shell clam population in the Black Sea exhibited the highest genetic similarity to Baltic populations, which confirmed the hypothesis that M. arenaria was introduced to the Gulf of Odessa from the Baltic Sea. The most enigmatic results were obtained for populations from the White Sea, which were characterized by high genetic affinity with American populations.

  13. The Effects of Air Exposure on Biomarkers of Mangrove Mud Clam (Polymesoda erosa)%露空对红树蚬生物标志物的影响

    Institute of Scientific and Technical Information of China (English)

    武文丽; 杨明柳; 吴斌; 廖思明; 吴志强; 阎冰

    2014-01-01

    [Objective]In this study,the effects of air exposure on responses of the biomarkers of mangrove mud clam (Polymesoda erosa )in transit was explored.[Methods]The clams,after being exposed to air for 8h at 8℃,26℃ and 35℃,were placed back in seawater of 26℃ for 3h, 6h,12h and 24h,respectively,and then six biomarkers of the clams haemolymph were meas-ured,including superoxide dismutase activity (SOD),catalase activity (CAT),acetylcholinest-erase activity (AChE),glutathione S-transferase activity (GST),ferric reducing antioxidant power (FRAP)and malodiadehyde content (MDA).[Results]Significant increases in SOD, CAT,AChE,GST,FRAP and MDA were observed in the clams exposed to air at 8℃ or 35℃. Significant increases in SOD,AChE and MDA,great decrease in GST,and slight decreases in CAT and FRAP were found in the clams exposed to air at 26℃.All six biomarkers recovered to their initial levels after the clams were put back in seawater for 24h,but they were found fluctuated within 24h.[Conclusion]The effects of air exposure on biomarkers of the calm were found to be significant.In all treatments,the lev-els of biomarkers of the clams exposed to air for 8h at 26℃ and then placed back in seawater for 3h to 6h were closest to their initial levels.%【目的】研究样品露空运输过程对红树蚬(Polymesoda erosa )生物标志物的影响。【方法】野外采集的红树蚬经8℃、26℃和35℃露空处理8h,随后在26℃海水中暂养恢复3h、6h、12h 和24h,测定红树蚬血液超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、乙酰胆碱酯酶(AChE)、谷胱甘肽转硫酶(GST)活性,以及铁还原力(FRAP)和丙二醛(MDA)含量。【结果】8℃和35℃露空处理,SOD、CAT、AChE、GST、FRAP 和 MDA 均显著升高。26℃露空处理,SOD、AChE 和 MDA 显著升高,GST 显著降低,CAT 和 FRAP 有所降低但不显著。经过暂养,红树蚬各项指标均能恢复到初始水平,但24h

  14. 菲律宾蛤仔幼虫食料的研究

    Institute of Scientific and Technical Information of China (English)

    周荣胜; 陈德富; 陈绍贵; 陈灿斯

    1984-01-01

    近年来,菲律宾蛤仔Ruditapes philippinarum(Adans et Reeve)土池人工育苗和垦区育苗已成为解决其种苗的重要途径。在人工育苗过程中,选择适宜的幼虫饵料,是提高其成活率重要措施之一。

  15. Implications for management and conservation of the population genetic structure of the wedge clam Donax trunculus across two biogeographic boundaries

    Science.gov (United States)

    Marie, Amandine D.; Lejeusne, Christophe; Karapatsiou, Evgenia; Cuesta, José A.; Drake, Pilar; MacPherson, Enrique; Bernatchez, Louis; Rico, Ciro

    2016-12-01

    In a resource management perspective, the understanding of the relative influence of the physical factors on species connectivity remains a major challenge and is also of great ecological and conservation biology interest. Despite the overfishing threat on the wedge clam Donax trunculus in Europe, relatively little information is known about its population genetic structure and connectivity and their consequences on conservation policies. We employed 16 microsatellite loci to characterise the genetic diversity and population structure of D. trunculus. A total of 514 samples from seven different localities along the Atlantic-Mediterranean transition, from the Atlantic (Gulf of Cádiz) to the north-western Mediterranean were genotyped. The analysis of the population genetic structure displayed a clear distinction along the Atlantic-Mediterranean transition with different clusters in the Atlantic Ocean, the Alboran Sea and the northwestern Mediterranean. Consequently, we recommend that these three areas should be considered as different management units. We showed that all populations seem to be at high long-term risk of extinction with the exception of the protected Doñana National Park population which still seems to have evolutionary potential. Therefore, our results emphasized the necessity of protection of this economic resource and the validity of molecular tools to evaluate the population dynamics.

  16. Impact of hypoxia on hemolymph contamination by uranium in an aquatic animal, the freshwater clam Corbicula fluminea

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Damien [Universite Bordeaux 1, CNRS, UMR 5805 EPOC, Place du Dr Peyneau, 33120 Arcachon (France)], E-mail: d.tran@epoc.u-bordeaux1.fr; Massabuau, Jean-Charles [Universite Bordeaux 1, CNRS, UMR 5805 EPOC, Place du Dr Peyneau, 33120 Arcachon (France)], E-mail: jc.massabuau@epoc.u-bordeaux1.fr; Garnier-Laplace, Jacqueline [Laboratoire de Radioecologie et Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat. 186, BP3, 13115 Saint Paul-Lez-Durance, Cedex (France)], E-mail: Jacqueline.Garnier-Laplace@irsn.fr

    2008-12-15

    Multi-stress situations are a major question and low-oxygenated waters (hypoxia) are a growing problem. Importantly, hypoxia stimulates the ventilatory flow rate in aquatic animals and this increases gill exposure to contaminants. Surprisingly, in the freshwater clam Corbicula fluminea, this is associated with increased bioaccumulation of uranium in gills but not in deep tissues. We searched for an explanation by analyzing hemolymph U-transport in Corbicula exposed to 0.36 {mu}M dissolved uranium at various O{sub 2}-levels for 10 days. In hypoxia, one observed an increased U concentration in the arterial hemolymph flowing from gills to tissues but this was not associated with an increased U concentration in the venous hemolymph nor in the other tissues. We conclude that the cardiac flow rate must have decreased to explain this absence of over-accumulation. In addition to its already known deleterious effects, uranium can thus deeply impair cardiac flow rate in exposed aquatic animals during multi-stress exposures. - Uranium contamination enhanced by hypoxia can deeply impair circulatory hemolymph flow in aquatic animals.

  17. Fine-scale spatial distribution of the common lugworm Arenicola marina, and effects of intertidal clam fishing

    Science.gov (United States)

    Boldina, Inna; Beninger, Peter G.

    2014-04-01

    Despite its ubiquity and its role as an ecosystem engineer on temperate intertidal mudflats, little is known of the spatial ecology of the lugworm Arenicola marina. We estimated lugworm densities and analyzed the spatial distribution of A. marina on a French Atlantic mudflat subjected to long-term clam digging activities, and compared these to a nearby pristine reference mudflat, using a combination of geostatistical techniques: point-pattern analysis, autocorrelation, and wavelet analysis. Lugworm densities were an order of magnitude greater at the reference site. Although A. marina showed an aggregative spatial distribution at both sites, the characteristics and intensity of aggregation differed markedly between sites. The reference site showed an inhibition process (regular distribution) at distances marina was clearly aggregated at both sites; however, the autocorrelation strength was much weaker at the impacted site. In addition, the non-impacted site presented multi-scale spatial distribution, which was not evident at the impacted site. The differences observed between the spatial distributions of the fishing-impacted vs. the non-impacted site reflect similar findings for other components of these two mudflat ecosystems, suggesting common community-level responses to prolonged mechanical perturbation: a decrease in naturally-occurring aggregation. This change may have consequences for basic biological characteristics such as reproduction, recruitment, growth, and feeding.

  18. Population biology and secondary production of the stout razor clam Tagelus plebeius (Bivalvia, Solecurtidae on a sandflat in southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Jolnnye R. Abrahão

    2010-02-01

    Full Text Available The population biology and production of the stout razor clam Tagelus plebeius Lightfoot, 1786 were investigated on an intertidal sandflat on the southeast coast of Brazil (Enseada Beach, São Sebastião, state of São Paulo between April 1997 and April 1998. Two rectangular sites of 50 X 10 m parallel to the waterline were established, site A (upper intertidal level and site B (middle intertidal level, where the samples were taken in an 0.5 x 0.5 m quadrat. High abundances were recorded in winter and spring, with no significant differences between the sites. The high bivalve abundances were related to the presence of very fine homogeneous sediment with low salinities. Tagelus plebeius had negative allometric growth, characteristic of deep burrowers for the relationships DM/SL and AFDM/SL. Parameters of the modified von Bertalanffy growth function were: L∞ = 67.01 mm, K = 1.73 year-1, t0 = -0.11 year, C = 0.43, WP = 0.96. The instantaneous mortality (Z was 3.12 year-1, relatively high in comparison to other tropical bivalve populations. Secondary production was 1.53 g AFDM m-2 year-1, with a P/B ratio reaching 1.37 year-1. This high turnover ratio (P/B was related to a rapid population replacement, connected with the short life span and high mortality of the species.

  19. Kistimonas scapharcae sp. nov., isolated from a dead ark clam (Scapharca broughtonii), and emended description of the genus Kistimonas.

    Science.gov (United States)

    Lee, Jina; Shin, Na-Ri; Lee, Hae-Won; Roh, Seong Woon; Kim, Min-Soo; Kim, Young-Ok; Bae, Jin-Woo

    2012-12-01

    A Gram-negative, motile, facultatively anaerobic rod, designated A36(T), was isolated from a dead ark clam found on the south coast of Korea. The isolate was catalase- and oxidase-negative. 16S rRNA gene sequence analysis indicated that strain A36(T) was most closely related to Kistimonas asteriae KMD 001(T), with which it shared 98.2% 16S rRNA gene sequence similarity. Strain A36(T) grew optimally at 30-37 °C, with 1% (w/v) NaCl and at pH 8.0. The major respiratory quinone was ubiquinone-9 (Q-9). The major polar lipids were phosphatidylserine, phosphoethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The major fatty acids were summed feature 3 (comprising C(16:1)ω7c and/or iso-C(15) 2-OH) and C(16:0). The genomic DNA G+C content was 47.3 mol%. DNA-DNA relatedness between the isolate and K. asteriae JCM 15607(T) was <25 ± 3%. Strain A36(T) represents a novel species of the genus Kistimonas, for which the name Kistimonas scapharcae sp. nov. is proposed. The type strain is A36(T) ( = KACC 16204(T)  = JCM 17805(T)). An emended description of the genus Kistimonas is also provided.

  20. Neptunomonas concharum sp. nov., isolated from a dead ark clam, and emended description of the genus Neptunomonas.

    Science.gov (United States)

    Lee, Hae-Won; Shin, Na-Ri; Lee, Jina; Roh, Seong Woon; Whon, Tae Woong; Bae, Jin-Woo

    2012-11-01

    A novel Gram-staining-negative, facultatively anaerobic, motile and rod-shaped bacterium, designated strain LHW37(T), was isolated from a dead ark clam collected on the south coast of Korea. The novel strain grew optimally at 37 °C, at pH 7.0-8.0 and with 2% (w/v) NaCl. The predominant cellular fatty acids were C(18:1)ω7c and summed feature 3 (C(16:1)ω7c and/or iso-C(15:0) 2-OH). The major isoprenoid quinone was ubiquinone-8 (Q-8) and the predominant polar lipids were phosphatidylethanolamine and phosphatidylglycerol. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the novel strain was most closely related to Neptunomonas japonica JAMM 0745(T) (97.1% sequence similarity). The genomic DNA G+C content of strain LHW37(T) was 48.2 mol%. The DNA-DNA relatedness values recorded in hybridization experiments between the novel strain and its closest known relative were ≤ 18%. Based on the phenotypic, genotypic and phylogenetic data, strain LHW37(T) represents a novel species belonging to the genus Neptunomonas for which the name Neptunomonas concharum sp. nov. is proposed. The type strain is LHW37(T) (=KACC 15543(T) =JCM 17730(T)). An emended description of the genus Neptunomonas is also provided.

  1. Combining ability and heterosis analysis over two environments in a diallel cross of three families of the clam Meretrix meretrix

    Institute of Scientific and Technical Information of China (English)

    DAI Ping; WANG Hongxia; XIAO Guoqiang; LIU Baozhong

    2014-01-01

    A 3×3 complete diallel cross comprising three families of the clam Meretrix meretrix (P1, P2 and P3) was used to determine the combining ability of parental families and heterosis of F1 under indoor and open-air environments for growth traits. Analysis of variance for shell length and whole body weight indicated highly significant cross effects, environment effects and the interaction of cross by environment. General combining ability (GCA) and specific combing ability exhibited great variation among crosses and between two environments. Pooled over environments, P2 was the top combiner among the three parental families for both traits studied. The cross of P1 and P3 had the highest SCA. Additionally, significant reciprocal effects were observed. For individual environment, about half of the crossbred combinations showed favorable Mid-parent heterosis (MPH) (>1%) for the shell length and whole body weight. Our data has shown that non-additive genetic and reciprocal effects constituted the major sources of genetic variation for both shell length and whole body weight, which indicates that crossbreeding among selective families could further explore the heterotic effects.

  2. Histological survey of symbionts and other conditions of pod razor clam Ensis siliqua (Linnaeus, 1758) in Galicia (NW Spain).

    Science.gov (United States)

    Ruiz, Maite; Darriba, Susana; Rodríguez, Rosana; López, Carmen

    2013-01-01

    The aim of the present study was to carry out a survey of parasites and other conditions affecting pod razor clam populations, Ensis siliqua, in two beds from Galicia (NW Spain). In Galicia, the production of E. siliqua has increased in recent years due to the development of specific plans for its exploitation, however few and quite recent pathological studies have been carried out in this species. The results of this study showed the presence of different protozoa as the more prevalent group, especially Nematopsis sp. gregarines, unidentified branchial protozoa, renal coccidia and Trichodina sp. ciliates. Larval stages of trematodes and neoplastic disorders were also observed with lower prevalences. Furthermore, an ultrastructural analysis of two types of unidentified basophilic inclusions, both found in the digestive gland, revealed the presence of icosahedral viral particles and prokaryotic organisms, respectively. None of the parasites detected in E. siliqua from this study was notifiable to the World Organisation for Animal Health (OIE) and the majority of the symbionts and conditions observed in their tissues did not cause host damage. Nevertheless, parasites like bucephalid digenean sporocysts, viral inclusions, prokaryotic infections, disseminated neoplasm or germinoma detected in some samples could cause moderate or severe damage to the host depending on the intensity of infection.

  3. Loss of genes related to Nucleotide Excision Repair (NER) and implications for reductive genome evolution in symbionts of deep-sea vesicomyid clams

    Science.gov (United States)

    Shimamura, Shigeru; Kaneko, Takashi; Ozawa, Genki; Matsumoto, Mamiko Nishino; Koshiishi, Takeru; Takaki, Yoshihiro; Kato, Chiaki; Takai, Ken; Yoshida, Takao; Fujikura, Katsunori; Barry, James P.

    2017-01-01

    Intracellular thioautotrophic symbionts of deep-sea vesicomyid clams lack some DNA repair genes and are thought to be undergoing reductive genome evolution (RGE). In this study, we addressed two questions, 1) how these symbionts lost their DNA repair genes and 2) how such losses affect RGE. For the first question, we examined genes associated with nucleotide excision repair (NER; uvrA, uvrB, uvrC, uvrD, uvrD paralog [uvrDp] and mfd) in 12 symbionts of vesicomyid clams belonging to two clades (5 clade I and 7 clade II symbionts). While uvrA, uvrDp and mfd were conserved in all symbionts, uvrB and uvrC were degraded in all clade I symbionts but were apparently intact in clade II symbionts. UvrD was disrupted in two clade II symbionts. Among the intact genes in Ca. Vesicomyosocius okutanii (clade I), expressions of uvrD and mfd were detected by reverse transcription-polymerase chain reaction (RT-PCR), but those of uvrA and uvrDp were not. In contrast, all intact genes were expressed in the symbiont of Calyptogena pacifica (clade II). To assess how gene losses affect RGE (question 2), genetic distances of the examined genes in symbionts from Bathymodiolus septemdierum were shown to be larger in clade I than clade II symbionts. In addition, these genes had lower guanine+cytosine (GC) content and higher repeat sequence densities in clade I than measured in clade II. Our results suggest that NER genes are currently being lost from the extant lineages of vesicomyid clam symbionts. The loss of NER genes and mutY in these symbionts is likely to promote increases in genetic distance and repeat sequence density as well as reduced GC content in genomic genes, and may have facilitated reductive evolution of the genome. PMID:28199404

  4. Effects of ocean acidification driven by elevated CO2 on larval shell growth and abnormal rates of the venerid clam, Mactra veneriformis

    Science.gov (United States)

    Kim, Jee-Hoon; Yu, Ok Hwan; Yang, Eun Jin; Kang, Sung-Ho; Kim, Won; Choy, Eun Jung

    2016-11-01

    The venerid clam ( Mactra veneriformis Reeve 1854) is one of the main cultured bivalve species in intertidal and shallow subtidal ecosystems along the west coast of Korea. To understand the effects of ocean acidification on the early life stages of Korean clams, we investigated shell growth and abnormality rates and types in the D-shaped, umbonate veliger, and pediveliger stages of the venerid clam M. veneriformis during exposure to elevated seawater pCO2. In particular, we examined abnormal types of larval shell morphology categorized as shell deformations, shell distortions, and shell fissures. Specimens were incubated in seawater equilibrated with bubbled CO2-enriched air at (400±25)×10-6 (ambient control), (800±25)×10-6 (high pCO2), or (1 200±28)×10-6 (extremely high pCO2), the atmospheric CO2 concentrations predicted for the years 2014, 2084, and 2154 (70-year intervals; two human generations), respectively, in the Representative Concentration Pathway (RCP) 8.5 scenario. The mean shell lengths of larvae were significantly decreased in the high and extremely high pCO2 groups compared with the ambient control groups. Furthermore, under high and extremely high pCO2 conditions, the cultures exhibited significantly increased abundances of abnormal larvae and increased severity of abnormalities compared with the ambient control. In the umbonate veliger stage of the experimental larvae, the most common abnormalities were shell deformations, distortions, and fissures; on the other hand, convex hinges and mantle protuberances were absent. These results suggest that elevated CO2 exerts an additional burden on the health of M. veneriformis larvae by impairing early development.

  5. Uptake of dissolved Ag, Cd, and Co by the clam, Macoma balthica: relative importance of overlying water, oxic pore water, and burrow water.

    Science.gov (United States)

    Griscom, Sarah B; Fisher, Nicholas S

    2002-06-01

    The facultative deposit-feeding clam Macoma balthica is used as a bioindicator organism for assessing coastal metal contamination. Previous work has evaluated the assimilation of metals from different possible food sources for this clam, but no studies have measured the uptake rates of metals from different dissolved sources. This study specifically compares three different dissolved sources: overlying water (SW), oxic pore water (OPW) from a depth of deposit feeding), and burrow water (BW) (a mixture of anoxic pore water and overlying water). Uptake rates of dissolved Ag, Cd, and Co in M. balthica were measured in short-term laboratory experiments using radiotracers. Clams were exposed to metals in water only for SW and surface OPW treatments. In the BW treatment, metal uptake was compared in clams placed in radiolabeled organic-poor or organic-rich sediment under conditions in which feeding was inhibited. Uptake rate constantsfrom SW for Ag, Cd, and Co were 0.35, 0.033, and 0.035 L g(-1) day(-1), respectively. Lower uptake of dissolved metals from OPW was noted but was only significant for Co. Metal uptake from BW and SW were also comparable; however, the trend showed lower Ag and higher Co uptake from BW. Metal distributions and concentrations in the two radiolabeled sediments were affected by active irrigation of SW into the burrows; dissolved metal concentrations in BW were approximately 30% lower than that in the bulk pore water concentrations. In the organic-rich sediment, Cd and Ag partitioned more in the dissolved phase (sensitivity analysis using measured rate constants for uptake and a range of metal concentrations from field studies suggested that, under most conditions, uptake of dissolved Ag is primarily from OPW, Co is mostly from BW, and Cd uptake varies depending on its concentration in each compartment. Little Co or Ag is likely to be taken up from SW, whereas 20-50% of Cd may be accumulated from this source. Thus, SW, OPW, and BW are all

  6. Studies on filtration rate in four species of suspension feeding bivalves

    Institute of Scientific and Technical Information of China (English)

    林元烧; 罗文新; 曹文清; 郭东晖; 郑爱榕; 黄长江

    2002-01-01

    The filtration rates of four kinds of bivalves that were cultivated dominantly around Xiamen sea area were measured by using a laboratory flowing system. The experimental results were shown below: (1) Filtration rates were measured in the range of 54~74.8 ml/ (g@min) among the four bivalves, sequencing descently Saccostrea cucullata > Sinonovacula constricta > Mytilus viridis > Ruditapes philippinarum. (2) The relationship between filtration rates on individual size showed a negative exponential function (FR = aWb, FR' = aWb-1), with b - 1 = - 0.435 6 and - 0.392. (3) Filtration rates on Skeletonema costatum were much higher than on Alexandrium tamarensis and Scrippsilla trochoidea inS. Cucullata and R. Philippinarum. (4) FR'on algal densities was also shown a negative function(FR' = aDb-1), with b-1 =-0.143 and-0.215 2 in S.cucullata and R.philippinarum, respectively.

  7. Four-stranded coiled-coil elastic protein in the byssus of the giant clam, Tridacna maxima.

    Science.gov (United States)

    Miserez, Ali; Li, Youli; Cagnon, Joel; Weaver, James C; Waite, J Herbert

    2012-02-13

    An elastic protein with a secondary structure distinct from all well-known load-bearing proteins is found in the byssus of the giant clam, Tridacna maxima . The byssus consists of a bundle of hundreds of individual threads, each measuring about about 100 μm in diameter, which exhibit a tendon-like mechanical response. The amino acid composition of Tridacna byssus, however, is unlike tendon collagen, lacking high glycine, proline, and hydroxyproline. Wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS) measurements suggest that the constituent nanofibrils of the byssal threads are distinct from known secondary structure motifs previously reported for elastic proteins including the collagen triple-helix, the β-sheet nanocrystalline domains of silks, or the double-stranded coiled-coil regions of intermediate filaments. Instead, X-ray diffraction data indicate a structural organization in which four coiled-coil α-helices form a stable rope-like structure, which then further pack in a pseudohexagonal lattice to form nanofibrils. Amino acid composition analysis shows unusually high concentrations of acidic as well as basic residues, suggesting that the four-helix structure is stabilized by strong ionic interactions between oppositely charged residues in neighboring strands. The composition also suggests additional stabilization by disulfide cross-linking. On a larger scale, scanning and conventional transmission electron microscope (STEM and TEM) observations indicate that the nanofibrils exhibit an alternating periodicity of about 500 nm along the axial direction. A molecular model that combines the mechanical properties with the structural characteristics of the Tridacna byssal threads is proposed.

  8. Veligers of the invasive Asian clam Corbicula fluminea in the Columbia River Basin: Broadscale distribution, abundance, and ecological associations

    Science.gov (United States)

    Hassett, Whitney; Bollens, Stephen M.; Counihan, Timothy D.; Rollwagen-Bollens, Gretchen; Zimmerman, Julie; Emerson, Joshua E.

    2017-01-01

    The invasive Asian clam Corbicula fluminea was introduced to North America in the 1930s and now inhabits most regions of the conterminous United States; however, the distribution and ecology of C. fluminea in the Columbia River Basin is poorly understood. During 2013 and 2014, 5 Columbia-Snake River reservoirs were sampled monthly from May through September, along with 23 additional lakes and reservoirs sampled once each summer. Associations among C. fluminea veligers, other components of the plankton, and environmental variables were analyzed using non-metric multidimensional scaling and canonical correspondence analysis. Corbicula fluminea veligers were found in high abundances in all mainstem Columbia-Snake River reservoirs, with an annual mean abundance of 71.2 individuals per cubic meter (inds./m3). Only 3 of 23 lakes and (non-mainstem) reservoirs contained C. fluminea, with abundances considerably lower (maximum = 21.2 inds./m3) than in the mainstem reservoirs. A diatom-dominated community preceded the spawning of C. fluminea in early summer at all sites. Corbicula fluminea veligers characterized the plankton community in late summer and were associated with cyanobacteria and high water temperatures. A third community, characterized by cyanobacteria, was apparent in non-mainstem sites in July and August. Our analyses describe the relationship of C. fluminea to the plankton community and environment, which contributes to our understanding of the possible effects of C. fluminea infestations and which waterbodies in the Columbia River Basin are at risk for infestation. Understanding the effects and environmental determinants of invasive mollusks will be increasingly important in the future with the possible arrival of zebra (Dreissena polymorpha) or quagga (D. bugensis) mussels to the region.

  9. Aggregation of a slow-folding mutant of a beta-clam protein proceeds through a monomeric nucleus.

    Science.gov (United States)

    Ignatova, Zoya; Gierasch, Lila M

    2005-05-17

    Mechanistic understanding of protein aggregation, leading either to structured amyloid fibrils or to amorphous inclusion body-like deposits, should facilitate the identification of potential therapeutic intervention strategies for the devastating amyloid-based diseases. Here we focus on the in vitro aggregation of a slow-folding mutant of the beta-clam protein, cellular retinoic acid-binding protein I (P39A CRABP I), which forms inclusion bodies when expressed in Escherichia coli. Aggregation was monitored by observing the fluorescence of a fluorescein-based biarsenical dye (FlAsH) that ligates to a tetra-Cys motif, here incorporated into a flexible Omega-loop. The fluorescence signal of FlAsH on the tetra-Cys-containing P39A CRABP I is sensitive to whether this protein is native or unfolded, and was used in combination with other techniques to follow aggregate formation. The aggregation time course is compatible with a nucleation-dependent polymerization model, and detailed kinetic analysis showed that the energetically unfavorable nucleus is monomeric. A similar conclusion was reached previously for poly(Gln) species [Chen, S., Ferrone, F. A., and Wetzel, R. (2002) Proc. Natl. Acad. Sci. U.S.A. 99, 11884-11889] and points to an unfavorable equilibrium between the misfolded intermediate and the bulk pool of monomers as causative in aggregation. The P39A mutation, which removes a helix-stop signal, may slow closure of the beta-barrel in P39A CRABP I relative to the wild type, leaving it vulnerable to aggregation. Wide-angle X-ray scattering showed that the amorphous aggregates formed by the aggregation-prone intermediates of P39A CRABP I contain predominantly beta-strands structured in a lamellar fashion with 10.03 A spacing between adjacent beta-sheets.

  10. Seasonal variation of biochemical components in clam ( Saxidomus purpuratus Sowerby 1852) in relation to its reproductive cycle and the environmental condition of Sanggou Bay, China

    Science.gov (United States)

    Bi, Jinhong; Li, Qi; Zhang, Xinjun; Zhang, Zhixin; Tian, Jinling; Xu, Yushan; Liu, Wenguang

    2016-04-01

    Seasonal variation of biochemical components in clam ( Saxidomus purpuratus Sowerby 1852) was investigated from March 2012 to February 2013 in relation to environmental condition of Sanggou Bay and the reproductive cycle of clam. According to the histological analysis, the reproductive cycle of S. purpuratus includes two distinctive phases: a total spent and inactive stage from November to January, and a gametogenesis stage, including ripeness and spawning, during the rest of the year. Gametes were generated at a low temperature (2.1°C) in February. Spawning took place once a year from June to October. The massive spawning occurred in August when the highest water temperature and chlorophyll a level could be observed. The key biochemical components (glycogen, protein and lipid) in five tissues (gonad, foot, mantle, siphon and adductor muscle) were analyzed. The glycogen content was high before gametogenesis, and decreased significantly during the gonad development in the gonad, mantle and foot of both females and males, suggesting that glycogen was an important energy source for gonad development. The protein and lipid contents increased in the ovary during the gonad development, demonstrating that they are the major organic components of oocytes. The lipid and protein contents decreased in the testis, implying that they can provide energy and material for spermatogenesis. The results also showed that protein stored in the mantle and foot could support the reproduction after the glycogen was depleted.

  11. Evaluación de la tasa de aclaración de la almeja dulceacuícola Anodontites tortolis en un medio con coliformes Escherichia coli Clearance rate of faecal coliforms by netropical freshwater clam

    Directory of Open Access Journals (Sweden)

    Juan René Mallama Leyton

    2011-01-01

    Full Text Available En condiciones de laboratorio se evaluón acute; la eficiencia de la almeja de agua dulce (Anodontites tortolis) para disminuir la carga de coliformes fecales (Escherichia coli) determinada mediante filtración en membrana por 8 horas. El experimento se diseñó con dos tratamientos (densidades de seis (T1) y ocho almejas (T2) más un control) con tres replicaciones. Se encontraron diferencias significativas (PUnder laboratory conditions the efficiency of the freshwater clam Anodontites tortolis to diminish the quantity of faecal coliforms, determined by the membrane filtration method during eight hours was evaluated. The experiment was design with two treatments (two densities of six (T1) and eight clams (T2) and a control) and three replications. Statistical significant differences (P<0.05) according to the Kruskal-Wallis test for the clearance rates were found. The highest levels of remotion of E. coli belonged to the treatment in which there was the highest number of individuals. The clearance rate of the clams varied between 0.47 and 3.80 l.h-1.ind-1 which is reported in the literature. Removal levels showing A. tortolis suggest that this clam can be used as a biological resource for the treatment of the tertiary waters contaminated with faecal coliform bacteria.

  12. Artificial radioactivity in edible parts of giant clam mollusc from Mururoa atoll from 1967 to 1990. Health physics aspect. Radioactivite artificielle dans les parties comestibles d'un mollusque (Benitier) de l'atoll de Mururoa entre 1967 et 1990. Interpretation sanitaire

    Energy Technology Data Exchange (ETDEWEB)

    Bablet, J.P.; Ducousso, R. (Service mixte de controle biologique, 91 - Montlhery (FR)); Arnould, C. (Laboratoire d' etudes et de surveillance de l' environnement, Papeete, Tahiti, (Polynesie francaise))

    1991-01-01

    Radionuclides concentration by giant clams is associated with feeding habit. It's also a main food for polynesian atolls inhabitants, elsewhere than Mururoa island because this mollusc is not consumed like all the other fishery products from this atoll lagoon. Nevertheless measurements of ten artificial radionuclides are performed in edible parts of giant clams fished from Mururoa lagoon since the beginning of nuclear tests. The decay of radionuclides concentration is described versus time. To go further on we have computed the dose-equivalent for internal exposure of an eventual giant clams eater. It is estimated that the resulting risk of malignancy is below than 1 per 10 000.

  13. Subcellular partitioning profiles and metallothionein levels in indigenous clams Moerella iridescens from a metal-impacted coastal bay

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zaosheng, E-mail: zswang@iue.ac.cn [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Boulevard, Xiamen 361021 (China); State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Feng, Chenglian; Ye, Chun [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Wang, Youshao [State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301 (China); Yan, Changzhou, E-mail: czyan@iue.ac.cn [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Boulevard, Xiamen 361021 (China); Li, Rui; Yan, Yijun; Chi, Qiaoqiao [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Boulevard, Xiamen 361021 (China)

    2016-07-15

    Highlights: • Subcellular partitioning profile of metals were investigated in biomonitor organism. • Cu, Zn and Cd levels in main fraction of HSP increase along accumulation gradients. • Despite MTs as the major binding pool, detoxification of Cd and Pb was incomplete. • Induced MTs were sequentially correlated with Cu, Zn and Cd levels in HSP fraction. • Intracellular metal fates highlighted the metabolic availability within organism. - Abstract: In this study, the effect of environmental metal exposure on the accumulation and subcellular distribution of metals in the digestive gland of clams with special emphasis on metallothioneins (MTs) was investigated. Specimens of indigenous Moerella iridescens were collected from different natural habitats in Maluan Bay (China), characterized by varying levels of metal contamination. The digestive glands were excised, homogenized and six subcellular fractions were separated by differential centrifugation procedures and analyzed for their Cu, Zn, Cd and Pb contents. MTs were quantified independently by spectrophotometric measurements of thiols. Site-specific differences were observed in total metal concentrations in the tissues, correlating well with variable environmental metal concentrations and reflecting the gradient trends in metal contamination. Concentrations of the non-essential Cd and Pb were more responsive to environmental exposure gradients than were tissue concentrations of the essential metals, Cu and Zn. Subcellular partitioning profiles for Cu, Zn and Cd were relatively similar, with the heat-stable protein (HSP) fraction as the dominant metal-binding compartment, whereas for Pb this fraction was much less important. The variations in proportions and concentrations of metals in this fraction along with the metal bioaccumulation gradients suggested that the induced MTs play an important role in metal homeostasis and detoxification for M. iridescens in the metal-contaminated bay. Nevertheless

  14. Long-term toxicity of hexabromocyclododecane (HBCDD) to the benthic clam Macoma balthica (L.) from the Baltic Sea

    Energy Technology Data Exchange (ETDEWEB)

    Smolarz, Katarzyna, E-mail: oceksm@univ.gda.pl [University of Gdansk, Institute of Oceanography, Laboratory of Ecosystem Functioning, al Pilsudskiego 46, 81-378 Gdynia (Poland); Soedertoern University College, School of Life Sciences, Alfred Nobels alle 7, 141 89 Huddinge (Sweden); Berger, Agata [University of Gdansk, Institute of Oceanography, Laboratory of Ecosystem Functioning, al Pilsudskiego 46, 81-378 Gdynia (Poland)

    2009-11-27

    The world's largest brackish water sea area, the Baltic Sea, is considered to be one of the most polluted seas of the world. Many new pollutants are constantly entering the environment, such as brominated flame-retardants (BFRs). BFRs represent a group of compounds that structurally resemble hydrophobic organic contaminants, but only scarce data about their toxicity to marine organism exist. Thus, the purpose of this study was to analyze long-term in vivo cytotoxicity and genotoxicity of hexabromocyclodododecane (HBCDD) to exposed marine invertebrates using a suite of cytogenetic biomarkers. This included a set of nuclear and nucleolar characteristics and the micronucleus test. The use of those parameters reflects different mechanisms of nuclear activity regulation in cells (as a parameter of cytotoxicity) and measures subcellular processes. The induction of nuclear abnormalities (like the formation of micronuclei) was also employed here as a parameter of genotoxicity. In order to reflect the proliferative and metabolic activity of the cells the number of argylophillic nucleolar organiser regions (NORs) in interphase cells was scored. Over a period of 50 days an in vivo exposure experiment with a clam Macoma balthica and different concentrations of HBCDD (nominal concentrations of 0, 100 and 250 {mu}g/l) with three replicates each was performed. Gill cells were used as 'sentinel systems' considering specificity in metabolism, repair mechanisms, adaptative response and cell proliferation. A significant increase in nuclear and nucleolar abnormalities and in the frequency of dead cells was observed during the duration of the experiment with the highest peak occurring 10 days after exposure for nuclear abnormalities and 20-30 days after exposure for malfunction of ribosomal genes (NORs) (GLM analyses and Spearman correlation, p < 0.05). Thus, the induction of micronuclei and other nuclear abnormalities reflected the toxic potential of HBCDD to marine

  15. A Study of the Soft Clam (Mya arenaria) Population on Some of the Mud Flats Within the Boundaries of the Parker River National Wildlife Refuge, Essex County, Massachusetts, with respect to the possible changes brought about by the influx of Black duck

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Several investigators working on the food habits of the black duck (Anas rubripes), have reported the presence of soft clams (Mya arenaria), in their stomachs and...

  16. Quantitative Risk Assessment of Vibrio Parahaemolyticus in Short Necked Clam%杂色蛤中副溶血弧菌的定量风险评估

    Institute of Scientific and Technical Information of China (English)

    李寿崧; 吴英娇; 宁芊; 吴文忠; 方成俊

    2012-01-01

    基于国际食品法典委员会关于微生物定量风险评估的理论框架,研究了从水产品批发市场到各零售点(主要为超市)杂色蛤中副溶血弧菌的动态变化情况,对因食用杂色蛤感染副溶血弧菌而引发疾病的风险进行预测,预测出每年、每人因消费生杂色蛤而导致由副溶血弧菌引发的食源性疾病的可能平均值被估计为1.65×10-8.同时对杂色蛤的另一种食用模式——烧烤,也进行了分析研究,确定因其所导致的风险十分小,可以不作为评估的对象.最后根据研究的结果提出针对政府监管部门的管理以及商业运营者和消费者的建议,这些风险管理措施、控制程序和安全食用规范的实施,均可大大降低因食用杂色蛤而感染副溶血弧菌并引发疾病的风险.%The dynamic variation of V. parahaemolyticus in short necked clam from the aquatic wholesale market to each point-of-sale (mainly for the supermarket) was studied based on theory framework of in- ternational food Codex Alimentarius Commission (CAC) about quantitative microbial risk assessment, combined with the reality of China and Fujian province. At the same time, the density of V. parahaemo- lyticus was detected by sampling from point-of-sale to compare with the prediction. Based on the Probabil- ity density of V. parahaemolyticus in short necked clam and the estimated number of servings consumed, the risk prediction of getting disease by consuming raw short necked clam is 1.65 ×10-8 per year. Mean- while, it also come to a conclusion that it is not necessary to analyze the risk which was caused by another cooking model barbecue, because of its minimum probability. Finally, some advices were proposed for government management, business operations and consumers. The implementation of these risk man- agement measures, control procedures and safety eating standards, would be helpful to reduce the risk of disease greatly infected by V

  17. Characterization of a long-chain fatty acid-CoA ligase 1 gene and association between its SNPs and growth traits in the clam Meretrix meretrix.

    Science.gov (United States)

    Dai, Ping; Huan, Pin; Wang, Hongxia; Lu, Xia; Liu, Baozhong

    2015-07-25

    Long-chain fatty acid-CoA ligases (ACSLs) play crucial roles in fatty acid (FA) metabolism. They convert free long-chain FA into acyl-CoAs, which are key intermediates in both anabolic and catabolic pathways. A long-chain fatty acid-CoA ligase gene was cloned in the clam Meretrix meretrix (MmeACSL1), with a full-length cDNA of 1865 bp encoding 475 amino acids. Its expression was only detected in hepatopancreas by semi-quantitative reverse transcription PCR. Expression level of MmeACSL1 exhibited a significant increase in a starvation experiment (Pgrowth traits (Pgrowth-related (Pgrowth traits of M. meretrix.

  18. Influence of parental sample sizes on the estimating genetic parameters in cultured clamMeretrix meretrix based on factorial mating designs

    Institute of Scientific and Technical Information of China (English)

    LIANG Bingbing; YUE Xin; WANG Hongxia; LIU Baozhong

    2016-01-01

    The precise and accurate knowledge of genetic parameters is a prerequisite for making efficient selection strategies in breeding programs. A number of estimators of heritability about important economic traits in many marine mollusks are available in the literature, however very few research have evaluated about the accuracy of genetic parameters estimated with different family structures. Thus, in the present study, the effect of parent sample size for estimating the precision of genetic parameters of four growth traits in clamM. meretrix by factorial designs were analyzed through restricted maximum likelihood (REML) and Bayesian. The results showed that the average estimated heritabilities of growth traits obtained from REML were 0.23–0.32 for 9 and 16 full-sib families and 0.19–0.22 for 25 full-sib families. When using Bayesian inference, the average estimated heritabilities were 0.11–0.12 for 9 and 16 full-sib families and 0.13–0.16 for 25 full-sib families. Compared with REML, Bayesian got lower heritabilities, but still remained at a medium level. When the number of parents increased from 6 to 10, the estimated heritabilities were more closed to 0.20 in REML and 0.12 in Bayesian inference. Genetic correlations among traits were positive and high and had no significant difference between different sizes of designs. The accuracies of estimated breeding values from the 9 and 16 families were less precise than those from 25 families. Our results provide a basic genetic evaluation for growth traits and should be useful for the design and operation of a practical selective breeding program in the clamM. meretrix.

  19. Expression of genes involved in the uptake of inorganic carbon in the gill of a deep-sea vesicomyid clam harboring intracellular thioautotrophic bacteria.

    Science.gov (United States)

    Hongo, Yuki; Ikuta, Tetsuro; Takaki, Yoshihiro; Shimamura, Shigeru; Shigenobu, Shuji; Maruyama, Tadashi; Yoshida, Takao

    2016-07-10

    Deep-sea vesicomyid clams, including the genus Phreagena (formerly Calyptogena), harbor thioautotrophic bacterial symbionts in the host symbiosome, which consists of cytoplasmic vacuoles in gill epithelial cells called bacteriocytes. The symbiont requires inorganic carbon (Ci), such as CO2, HCO3(-), and CO3(2-), to synthesize organic compounds, which are utilized by the host clam. The dominant Ci in seawater is HCO3(-), which is impermeable to cell membranes. Within the bacteriocyte, cytoplasmic carbonic anhydrase (CA) from the host, which catalyzes the inter-conversion between CO2 and HCO3(-), has been shown to be abundant and is thought to supply intracellular CO2 to symbionts in the symbiosome. However, the mechanism of Ci uptake by the host gill from seawater is poorly understood. To elucidate the influx pathway of Ci into the bacteriocyte, we isolated the genes related to Ci uptake via the pyrosequencing of cDNA from the gill of Phreagena okutanii, and investigated their expression patterns. Using phylogenetic and amino acid sequence analyses, three solute carrier family 4 (SLC4) bicarbonate transporters (slc4co1, slc4co2, and slc4co4) and two membrane-associated CAs (mcaco1 and mcaco2) were identified as candidate genes for Ci uptake. In an in situ hybridization analysis of gill sections, the expression of mcaco1 and mcaco2 was detected in the bacteriocytes and asymbiotic non-ciliated cells, respectively, and the expression of slc4co1 and slc4co2 was detected in the asymbiotic cells, including the intermediate cells of the inner area and the non-ciliated cells of the external area. Although subcellular localizations of the products of these genes have not been fully elucidated, they may play an important role in the uptake of Ci into the bacteriocytes. These findings will improve our understanding of the Ci transport system in the symbiotic relationships of chemosynthetic bivalves.

  20. Analogy in CLAM

    OpenAIRE

    Melis, Erica

    1999-01-01

    CL A M is a proof planner, developed by the Dream group in Edinburgh,that mainly operates for inductive proofs. This paper addresses the questionhow an analogy model that I developed independently of CL A M can beapplied to CL A M and it presents analogy-driven proof plan construction as acontrol strategy of CL A M . This strategy is realized as a derivational analogythat includes the reformulation of proof plans. The analogical replay checkswhether the reformulated justifications of the sour...

  1. Influences of Salinity Stress on Energy Metabolism in Blood Clam Tegillarca granosa%盐度胁迫对泥蚶能量代谢的影响

    Institute of Scientific and Technical Information of China (English)

    冀德伟; 陈琛; 李婷婷; 刘伟成; 曾国权; 柴雪良

    2016-01-01

    在水温(26.4±0.79)℃、盐度11、14.5、18、21.5、25和28.5下,将壳长27~28 mm泥蚶饲养在流水系统中24 h ,每一盐度梯度设置3个平行和3个空白对照,以研究盐度对泥蚶摄食、代谢、碳收支及能量代谢的影响。试验结果显示,随着盐度的升高,泥蚶的滤水率、摄食率、吸收率和O∶ N均先升后降,而耗氧率与排氨率先降后升,在盐度18~21.5时显著达到极值( P<0.05),但盐度对泥蚶的耗氧率、排氨率和O∶N影响不显著(P>0.05)。泥蚶代谢所需要的能量主要由脂肪和碳水化合物提供,盐度18~21.5为泥蚶的适宜盐度范围,此时的能量代谢方程分别为:100C=26.12F+30.75R+5.78U+37.35P;100C=25.06F+32.03R+5.15U+37.76P。%Influences of salinity on feeding ,metabolic physiology ,carbon budget and energy metabolism were studied in blood clam Tegillarca granosa with shell length of 27—28 mm exposed to a salinity of 11 , 14 .5 ,18 ,21 .5 ,25 and 28 .5 in a recirculating system for 24 hours at water temperature of (26 .4 ± 0 .79)℃ .The results showed that the filtration rate ,ingestion rate ,absorption rate and O∶N were increased at first and then decreased ,and the oxygen consumption rate and ammonia excretion rate decreased at first and then increased with the increasing salinity ,with the extreme value at the salinity from 18 to 21 .5(P0 .05) .The findings indicated that metabolic energy of the shellfish was primarily provided by fat and carbohydrates ,and that the blood clam had the energy budge equation of 100C=26 .12F+30 .75R+5 .78U+37 .35P at a salinity of 18 ,and of 100C=25 .06F+32 .03R+5 .15U+37 .76P at a salinity of 21 .5 ,which salinity from 18 to 21 .5 is of the optimal salinity range for growth in blood clam .

  2. Dynamics and chemistry of vortex remnants in late Arctic spring 1997 and 2000: Simulations with the Chemical Lagrangian Model of the Stratosphere (CLaMS

    Directory of Open Access Journals (Sweden)

    P. Konopka

    2003-01-01

    Full Text Available High-resolution simulations of the chemical composition of the Arctic stratosphere during late spring 1997 and 2000 were performed with the Chemical Lagrangian Model of the Stratosphere (CLaMS. The simulations were performed for the entire northern hemisphere on two isentropic levels 450 K (~18 km and 585 K (~24 km. The spatial distribution and the lifetime of the vortex remnants formed after the vortex breakup in May 1997 display different behavior above and below 20 km. Above 20 km, vortex remnants propagate southward (up to 40°N and are "frozen in'' in the summer circulation without significant mixing. Below 20 km the southward propagation of the remnants is bounded by the subtropical jet. Their lifetime is shorter by a factor of 2 than that above 20 km, owing to significant stirring below this altitude. The behavior of vortex remnants formed in March 2000 is similar but, due to an earlier vortex breakup, dominated during the first 6 weeks after the vortex breakup by westerly winds, even above 20 km. Vortex remnants formed in May 1997 are characterized by large mixing ratios of HCl indicating negligible, halogen-induced ozone loss. In contrast, mid-latitude ozone loss in late boreal spring 2000 is dominated, until mid-April, by halogen-induced ozone destruction within the vortex remnants, and subsequent transport of the ozone-depleted polar air masses (dilution into the mid-latitudes. By varying the intensity of mixing in CLaMS, the impact of mixing on the formation of ClONO2 and ozone depletion is investigated. We find that the photochemical decomposition of HNO3 and not mixing with NOx-rich mid-latitude air is the main source of NOx within the vortex remnants in March and April 2000. Ozone depletion in the remnants is driven by ClOx photolytically formed from ClONO2. At the end of May 1997, the halogen-induced ozone deficit at 450 K poleward of 30°N amounts to ~12% with ~10% in the polar vortex and ~2% in well-isolated vortex remnants

  3. Abundance pattern of wedge clam Donax cuneatus (L.) in different spatial scale in the vicinity of a coastal nuclear power plant.

    Science.gov (United States)

    Hussain, K Jahir; Mohanty, A K; Satpathy, K K; Prasad, M V R

    2010-04-01

    Impact of thermal discharge from a coastal power station (Madras Atomic Power Station, southeast coast of India) on the spatial variability of Donax cuneatus abundance was assessed to determine the impact boundary. Totally, 20 sites were selected both on south and north side in increasing spatial scale from mixing zone, 12 locations were selected toward south side at a distance from 0 (near mixing point) to 2,000 m and eight location were selected toward north from the effluent mixing zone. Mean water temperature along the coast ranged from 29.1 +/-0.15 degrees C to 31.2 +/- 0.15 degrees C. Total organic carbon content in the sediment ranged from 0.27% to 0.70%. D. cuneatus population on the swash zone was ranged between 1.3 +/- 1.5 and 88.3 +/- 9.6 m(-2). Meager population of wedge clam was observed up to 100 m (S100) south from mixing point and abundance gradually increased in different spatial scale. Comparatively high abundance was observed from S400 and reached maximum at S1000 (64.0 +/- 3.6 m(-2)). Similar pattern was observed on north side too but less abundance was observed only up to 80 m (N80). Maximum abundance was observed at control location C3-N500 (88.3 +/- 9.6 m(-2)). Forty meters on either side of discharge point was highly impacted, 80 to 100 m toward plume flow (south) was moderately impacted, and 80 m north of mixing point also witnessed moderate impact. After 100 m (N100), north was not affected by effluents, whereas between 100 and 400 m, south was influenced slightly. Multivariate clustering pattern on the environmental variables of all sampling locations and population trend of D. cuneatus at those stations showed similarity. Present investigation unambiguously showed that the abundance pattern of D. cuneatus on the sandy beach of east coast of Kalpakkam is not governed by single major factor but due to the result of multiple interacting factors. The population size of the wedge clam with reference to the effect of power plant effluents and

  4. 砗磲研究现状及在我国南海开展养殖的前景%Giant clam research and prospect of aquaculture in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    周勤; 王玉芬; 姜秀凤

    2014-01-01

    砗磲是软体动物门瓣鳃纲砗磲科生物的统称,广泛分布于热带珊瑚礁海域。20世纪八九十年代,澳大利亚、美国以及菲律宾等太平洋岛屿国家集中开展了砗磲增养殖及与之相关的生理、生态和经济学等基础研究。砗磲通过与其共生的虫黄藻获得营养,这一特性使得砗磲生长速度极快。砗磲的单位面积保有量可达400t·hm-2,使得它们在热带珊瑚礁海域中具有重要的生态学和养殖意义。不仅如此,砗磲在其生长过程中所体现出来的珊瑚礁修复价值以及碳汇渔业价值对于海洋开发和保护都有着极其重要的意义。同时,我国南海拥有环境优越的广阔热带海域,可开展砗磲养殖的面积达3000km2以上。结合以上认识,作者认为砗磲养殖具有形成热带海洋贝类养殖重大产业的潜力,可以为我国南海珊瑚礁保护和生态文明建设工程提供支撑。%Giant clams are of the family Tridacnidae with 10 living species in only two genera, Tridacna and Hippopus. In the 1980s and 1990s, the Pacific Rim countries, including Australia, the Philippines and the U.S., conducted a series of joint research on the cultivation of giant clams and the relevant physiological, ecological and economic factors. The unique feature of giant clams among bivalve molluscs is their symbiotic relationship with dinoflagellate algae, zooxanthellae (Symbiodinium. sp); this gives them a nutritional and growth advantage over normal bivalve molluscs. Since the stocking of giant clams can reach 400 tonnes per hectare, giant clams have great significance to both mariculture sector and tropical coral reef ecosystem. Moreover, due to benefits to coral reef restoration and carbon sink fisheries, the growth of giant clams also has a significance for marine development and protection. Meantime The South China Sea has 3000 km2 tropical reef water, which is suitable for developing mariculture. We suggest that giant clams

  5. 不同饵料对短蛸生长的影响%Effects of Different Diets on Growth of Shot Arm Octopus Octopus ocellatus

    Institute of Scientific and Technical Information of China (English)

    朱文博; 孙玉忠; 赵宏远; 于美波; 郭见军; 李达

    2016-01-01

    在盐度28~30、水温23.6~25.8℃下,将54只初始体质量(34.82±3.79) g的健康短蛸放入500mL矿泉水瓶中,瓶体周身均匀钻直径5mm小孔约80个,每瓶1只,悬挂在4.1m×6.6m×1.4 m养殖池中,投喂菲律宾蛤仔、缢蛏和肉球近方蟹3种饵料,每种饵料3个平行组,比较分析3种饵料对短蛸生长的影响。28 d的饲养表明,3个饵料组的成活率均为100%,但投喂肉球近方蟹的短蛸特定生长率(1.67%/d)和饵料转化效率(33.46%)显著高于投喂缢蛏(1.33%/d ,14.01%)和菲律宾蛤仔(1.31%/d ,19.57%)的短蛸( P<0.05)。试验结果表明,蟹类是短蛸养成阶段较理想的饵料。%A 28‐d feeding trial was conducted to access the effects of three diets including Manila clam (Ruditapes philippinarum) ,razor clam (Sinonovacula constrzcta) and crab (Hemigrapsus sanguineus) on food intake ,weight gain ,specific growth rate and food conversion efficiency in short arm octopus (Oc‐topus ocellatus) with initial body weight of (34 .82 ± 3 .79) g .The octopus were reared in a 500 mL plastic bottle disposed in a tank of 4 .1 m × 6 .6 m × 1 .4 m at a rate of one individual per bottle and randomly as‐signed to 3 groups ,each of which was fed one of the three diets with 6 replicates at water temperature of 23 .6—25 .8 ℃ and a salinity of 28—30 for 28 days .It was found that the short arm octopus had 100% of survival in all treatment groups .However ,there were significantly higher specific growth rate (1 .67% /d) and food conversion efficiency (33 .46% ) in the octopus fed crab H .Sanguineus than those in the octopus fed razor clam (1 .33% /d and 14 .01% ) and Manila clam (1 .31% /d and 19 .57% ) ,indicating that crab was the best diet for short arm octopus culture .

  6. Seasonal Variations of Escherichia Coli Contamination in Clams (Chamelea Gallina) Harvested in the Adriatic Sea (San Benedetto del Tronto district, Italy)

    Science.gov (United States)

    Semeraro, Angela Marisa; Aliventi, Alessandra; Di Trani, Vittoria; Capocasa, Piero

    2014-01-01

    In the European Union, the classification of shellfish harvesting areas depends on levels of Escherichia coli checked in shellfish flesh and determines whether post-harvest treatment required before shellfish can be sold for human consumption. Nevertheless, intermittent sources of contamination, such as rainfall and runoff from agricultural and urban lands, may give rise to seasonal variations of E. coli concentration, hence an annual classification could not be correct. In this study, we investigated the microbial trend in clams (Chamelea gallina) harvested from the district of San Benedetto del Tronto, Italy. The Algaeadria database, a monitoring network for the whole Adriatic area, provided results from 2005 to 2012. E. coli values compliant and non-compliant with food safety criteria were evaluated by graphical data analysis tools and one-tailed Fisher’s exact test. The results showed a clear general seasonal trend and, in one of the considered areas, the non-compliant values from July to February were significantly lower than those from March to June (P<0.05). These findings may scientifically support a seasonal classification.

  7. Ocean acidification weakens the immune response of blood clam through hampering the NF-kappa β and toll-like receptor pathways.

    Science.gov (United States)

    Liu, Saixi; Shi, Wei; Guo, Cheng; Zhao, Xinguo; Han, Yu; Peng, Chao; Chai, Xueliang; Liu, Guangxu

    2016-07-01

    The impact of pCO2 driven ocean acidification on marine bivalve immunity remains poorly understood. To date, this impact has only been investigated in a few bivalve species and the underlying molecular mechanism remains unknown. In the present study, the effects of the realistic future ocean pCO2 levels (pH at 8.1, 7.8, and 7.4) on the total number of haemocyte cells (THC), phagocytosis status, blood cell types composition, and expression levels of twelve genes from the NF-kappa β signaling and toll-like receptor pathways of a typical bottom burrowing bivalve, blood clam (Tegillarca granosa), were investigated. The results obtained showed that while both THC number and phagocytosis frequency were significantly reduced, the percentage of red and basophil granulocytes were significantly decreased and increased, respectively, upon exposure to elevated pCO2. In addition, exposure to pCO2 acidified seawater generally led to a significant down-regulation in the inducer and key response genes of NF-kappa β signaling and toll-like receptor pathways. The results of the present study revealed that ocean acidification may hamper immune responses of the bivalve T. granosa which subsequently render individuals more susceptible to pathogens attacks such as those from virus and bacteria.

  8. A novel widespread cryptic species and phylogeographic patterns within several giant clam species (Cardiidae: Tridacna from the Indo-Pacific Ocean.

    Directory of Open Access Journals (Sweden)

    Thomas Huelsken

    Full Text Available Giant clams (genus Tridacna are iconic coral reef animals of the Indian and Pacific Oceans, easily recognizable by their massive shells and vibrantly colored mantle tissue. Most Tridacna species are listed by CITES and the IUCN Redlist, as their populations have been extensively harvested and depleted in many regions. Here, we survey Tridacna crocea and Tridacna maxima from the eastern Indian and western Pacific Oceans for mitochondrial (COI and 16S and nuclear (ITS sequence variation and consolidate these data with previous published results using phylogenetic analyses. We find deep intraspecific differentiation within both T. crocea and T. maxima. In T. crocea we describe a previously undocumented phylogeographic division to the east of Cenderawasih Bay (northwest New Guinea, whereas for T. maxima the previously described, distinctive lineage of Cenderawasih Bay can be seen to also typify western Pacific populations. Furthermore, we find an undescribed, monophyletic group that is evolutionarily distinct from named Tridacna species at both mitochondrial and nuclear loci. This cryptic taxon is geographically widespread with a range extent that minimally includes much of the central Indo-Pacific region. Our results reinforce the emerging paradigm that cryptic species are common among marine invertebrates, even for conspicuous and culturally significant taxa. Additionally, our results add to identified locations of genetic differentiation across the central Indo-Pacific and highlight how phylogeographic patterns may differ even between closely related and co-distributed species.

  9. The usability of ark clam shell (Anadara granosa) as calcium precursor to produce hydroxyapatite nanoparticle via wet chemical precipitate method in various sintering temperature.

    Science.gov (United States)

    Khiri, Mohammad Zulhasif Ahmad; Matori, Khamirul Amin; Zainuddin, Norhazlin; Abdullah, Che Azurahanim Che; Alassan, Zarifah Nadakkavil; Baharuddin, Nur Fadilah; Zaid, Mohd Hafiz Mohd

    2016-01-01

    This paper reported the uses of ark clam shell calcium precursor in order to form hydroxyapatite (HA) via the wet chemical precipitation method. The main objective of this research is to acquire better understanding regarding the effect of sintering temperature in the fabrication of HA. Throughout experiment, the ratio of Ca:P were constantly controlled, between 1.67 and 2.00. The formation of HA at these ratio was confirmed by means of energy-dispersive X-ray spectroscopy analysis. In addition, the effect of sintering temperature on the formation of HA was observed using X-ray diffraction analysis, while the structural and morphology was determined by means of field emission scanning electron microscopy. The formation of HA nanoparticle was recorded (~35-69 nm) in the form of as-synthesize HA powder. The bonding compound appeared in the formation of HA was carried out using Fourier transform infrared spectroscopy such as biomaterials that are expected to find potential applications in orthopedic and biomedical industries .

  10. CLAM钢TIG焊后的热处理工艺研究%Study on the heat treatment of CLAM steel joined by TIG

    Institute of Scientific and Technical Information of China (English)

    乔建生; 黄依娜; 万发荣

    2009-01-01

    为了解决利用钨极氩弧(TIG)焊方法焊接的CLAM钢在焊缝区存在的强度、硬度增加而韧性减弱的问题,从回火温度、回火时间以及重复回火等方面研究了回火对焊缝区硬度的影响,得到了回火温度选择为760℃、回火时间选择为2 h和在760℃保温1 h回火,重复进行两次的两种最佳热处理工艺.%Vickers hardness of the weld metal was bigger than Vickers hardness of the base metal in the China low activation martensitic (CLAM) steel which was joined by tungsten inert gas (TIG) welding. To reduce Vickers hardness of the weld metal, the specimen was tempered at different temperature for different time. Also the specimen was repeated tempering at 760 ℃ for one hour. Vickers hardness of the weld metal was the same as Vickers hardness of the base metal after tempering at 760℃ for two hours and tempering at 760 ℃ for one hour twice.

  11. Concentrations of Contaminants with Regulatory Limits in Samples of Clam (Chamelea gallina) Collected along the Abruzzi Region Coast in Central Italy.

    Science.gov (United States)

    Visciano, Pierina; Scortichini, Giampiero; Suzzi, Giovanna; Diletti, Gianfranco; Schirone, Maria; Martino, Giuseppe

    2015-09-01

    Concentrations of pollutants with regulatory limits were determined in specimens of Chamelea gallina, a species of clam collected along the Abruzzi coastal region of the central Adriatic Sea. Nine sampling sites were selected to evaluate the distribution of contaminants in the environment and the health risk for consumers. The concentrations of all the examined compounds were lower than the maximums set by European legislation. Polycyclic aromatic hydrocarbons and total mercury were below the detection limit (0.18 μg/kg for benzo[a]anthracene, 0.30 μg/kg for chrysene, 0.12 μg/kg for benzo[b]fluoranthene, 0.08 μg/kg for benzo[a]pyrene, and 0.0050 mg/kg for total mercury) in all the analyzed samples. Mean concentrations of lead and cadmium were 0.104 and 0.110 mg/kg, respectively. Of the non-dioxin-like polychlorinated biphenyls, PCB-153, PCB-180, and PCB-138 were the most abundant at all sampling sites (1a to 9a) at 0.25 mi (ca. 0.4 km) and at some sampling sites (1b, 2b, 3b, 5b and 7b) at 0.35 mi (ca. 0.56 km). Principal component analysis revealed that the concentrations of dioxin-like polychlorinated biphenyls were similar at the majority of sampling sites, and O8CDD and 2,3,7,8-T4CDF were the predominant dioxin congeners.

  12. Propidium Monoazide Integrated with qPCR Enables the Detection and Enumeration of Infectious Enteric RNA and DNA Viruses in Clam and Fermented Sausages

    Science.gov (United States)

    Quijada, Narciso M.; Fongaro, Gislaine; Barardi, Célia R. M.; Hernández, Marta; Rodríguez-Lázaro, David

    2016-01-01

    The increase of foodborne viral outbreaks highlights the need for a rapid and sensitive method for the prediction of viral infectivity in food samples. This study assesses the use of propidium monoazide (PMA) coupled with real-time PCR methods (RT-qPCR or qPCR for RNA or DNA viruses, respectively) in the determination of viral infectivity in complex animal-related food matrices. Clam and Spanish fermented sausage (“chorizo”) samples were spiked with infectious and heat-inactivated human adenovirus-2 (HAdV-2) and mengovirus (vMC0). PMA-qPCR/RT-qPCR discriminated infective virus particles, with significant reductions (>2.7 log10 or 99.7%). Additionally, infectious HAdV-2 and vMC0 were quantified by plaque assay (in plaque forming units, PFU), and compared with those in virus genomes copies (GCs) quantified by PMA-qPCR/RT-qPCR. A consistent correlation (R2 > 0.92) was showed between PFU and GCs along serial 10-fold dilutions in both DNA and RNA virus and in both food matrices. This study shows the use of PMA coupled to qPCR/RT-qPCR as a promising alternative for prediction of viral infectivity in food samples in comparison to more expensive and time-consuming methods and for those viruses that are not able to grow under available cell culture techniques. PMID:28018329

  13. The assessment of environmental pollution along the coast of Beibu Gulf, northern South China Sea: an integrated biomarker approach in the clam Meretrix meretrix.

    Science.gov (United States)

    Meng, Fanping; Wang, Zhifeng; Cheng, Fenglian; Du, Xiuping; Fu, Wenchao; Wang, Qun; Yi, Xiaoyan; Li, Yongfu; Zhou, You

    2013-04-01

    The clam Meretrix meretrix was used as a biomonitor to implement an environmental monitoring program along the coast of Beibu Gulf in October 2011. This program not only analyzed biomarkers including acetylcholinesterase, glutathione peroxidase, glutathione S-transferase, catalase and superoxide dismutase activities, total glutathione content and lipid peroxidation level in M. meretrix but also adopted a multi-biomarker approach - integrated biomarker response (IBR) to assess the environmental quality in this ecosystem. In addition, the metal (Hg, As, Cu, Pb, Zn, Cd and Cr) and polychlorinated biphenyls (PCBs) content in the surface sediment at the study area were also measured. The results showed that IBR index was able to distinguish a space trend between sampling sites with different degrees of anthropogenic environmental stress. Integrated contamination degree were displayed in the form of star plots and compared to IBR plots. There was a visual consistency between the pollution level and IBR variation. Based on the results, it was proved that the IBR method coupled with chemical analysis was quite useful for the assessment of environmental pollution in the coastal system.

  14. Propidium Monoazide Integrated with qPCR Enables the Detection and Enumeration of Infectious Enteric RNA and DNA Viruses in Clam and Fermented Sausages.

    Science.gov (United States)

    Quijada, Narciso M; Fongaro, Gislaine; Barardi, Célia R M; Hernández, Marta; Rodríguez-Lázaro, David

    2016-01-01

    The increase of foodborne viral outbreaks highlights the need for a rapid and sensitive method for the prediction of viral infectivity in food samples. This study assesses the use of propidium monoazide (PMA) coupled with real-time PCR methods (RT-qPCR or qPCR for RNA or DNA viruses, respectively) in the determination of viral infectivity in complex animal-related food matrices. Clam and Spanish fermented sausage ("chorizo") samples were spiked with infectious and heat-inactivated human adenovirus-2 (HAdV-2) and mengovirus (vMC0). PMA-qPCR/RT-qPCR discriminated infective virus particles, with significant reductions (>2.7 log10 or 99.7%). Additionally, infectious HAdV-2 and vMC0 were quantified by plaque assay (in plaque forming units, PFU), and compared with those in virus genomes copies (GCs) quantified by PMA-qPCR/RT-qPCR. A consistent correlation (R(2) > 0.92) was showed between PFU and GCs along serial 10-fold dilutions in both DNA and RNA virus and in both food matrices. This study shows the use of PMA coupled to qPCR/RT-qPCR as a promising alternative for prediction of viral infectivity in food samples in comparison to more expensive and time-consuming methods and for those viruses that are not able to grow under available cell culture techniques.

  15. Propidium monoazide integrated with qPCR enables the detection and enumeration of infectious enteric RNA and DNA viruses in clam and fermented sausages

    Directory of Open Access Journals (Sweden)

    Narciso M Quijada

    2016-12-01

    Full Text Available The increase of foodborne viral outbreaks highlights the need for a rapid and sensitive method for the prediction of viral infectivity in food samples. This study assesses the use of propidium monoazide (PMA coupled with real-time PCR methods (RT-qPCR or qPCR for RNA or DNA viruses, respectively in the determination of viral infectivity in complex animal-related food matrices. Clam and Spanish fermented sausage (chorizo samples were spiked with infectious and heat-inactivated human adenovirus-2 (HAdV-2 and mengovirus (vMC0. PMA-qPCR/RT-qPCR discriminated infective virus particles, with significant reductions (>2.7 log10 or 99.7%. Additionally, infectious HAdV-2 and vMC0 were quantified by plaque assay (in plaque forming units, PFU, and compared with those in virus genomes copies (GCs quantified by PMA-qPCR/RT-qPCR. A consistent correlation (R2 > 0.92 was showed between PFU and GCs along serial ten-fold dilutions in both DNA and RNA virus and in both food matrices. This study shows the use of PMA coupled to qPCR/RT-qPCR as a promising alternative for prediction of viral infectivity in food samples in comparison to more expensive and time-consuming methods and for those viruses that are not able to grow under available cell culture techniques.

  16. A novel paramyxean parasite, Marteilia octospora n. sp. (Cercozoa) infecting the Grooved Razor Shell clam Solen marginatus from Galicia (NW Spain).

    Science.gov (United States)

    Ruiz, Maite; López, Carmen; Lee, Ren-Shiang; Rodríguez, Rosana; Darriba, Susana

    2016-03-01

    Protozoan parasites of the genus Marteilia have been detected in marine bivalves and other invertebrates around the world, associated in some cases with mass mortalities. The present paper reports the characterization of the Marteilia sp. protozoan infecting the digestive gland of the Grooved Razor Shell clam (Solen marginatus) from Galicia (NW Spain), proposing a novel species in the genus: Marteilia octospora n. sp. Morphological and molecular techniques were used for the description of this parasite. Tissue imprints were essential in the study to confirm the presence of 8 spores per sporangium, a number never reported in other species from this genus. An ultrastructural study revealed that the size and number of dense granules, free in the mature sporangia, were quite different from granules in other Marteilia spp. Another morphological difference is the absence of a layer of concentric membranes found surrounding the mature spore in other species. In addition, concentric membranous structures observed in the different stages of the parasite have never been mentioned in other species of genus Marteilia. Moreover, molecular analysis of the rDNA intergenic spacer (IGS) and the internal transcribed spacer (ITS-1) showed differences with the sequences available for other Marteilia spp.

  17. Estimation of Carrying Capacity of Manila Clam (Ruditapesphilippinarum) Culture Pond in Houhai Reclamation Area of Putian city,China%莆田后海垦区菲律宾蛤仔养殖池养殖容量的估算

    Institute of Scientific and Technical Information of China (English)

    杨淑芳; 张磊; 阎希柱

    2016-01-01

    From August 2013 to January 2014,the chlorophyll -a,primary productivity of phytoplankton,clams mortality rate in Houhai reclamation area of Putian were determined.The carrying capacity of the two Manila clam ponds wereestimated by Parsons TR-Takahashi M Ecological Trophodynamicsmodel [P=(BEn )×k]and Tait coastal energy flowing analysis model {B=[(0.1×C)/Q]×k}.Taking into consideration of the unused prima-ry productivity due to the pond effluent,the corrected results of two models were 5.52t and 7.10t for pond 1,with an average of 6.31t;3.60t and 4.62t for pond 2,with an average of 4.11t for two ponds.The actual yields of the two ponds accounted for 59.43%and 97.32%of the estimated capacities respectively.Two ponds of clam mortality rates were 23.43%and 22.5%,respectively.The capacity of pond 1 was significantly larger than that of pond 2.The pos-sible reasons are as follows:chl-a,the shapes of the pond,location and management.The carrying capacity of pond 2 was close to its actual yield.The estimated suitable breeding densities of Manila clam for pond 1 and for pond 2 were 0.61kg/m2 and 0.40kg/m2 respectively.As the actual breeding densities of two ponds are 0.19kg/m2 for each pond. The estimated suitable breeding density of Manila clam calculated from the carrying capacity was larger than the actu-al breeding density.A certain potential to increase the number of breeding clam exists.%2013年8月—2014年2月,对莆田后海垦区菲律宾蛤仔反季节高效生态养殖池叶绿素a、浮游植物初级生产量、蛤仔死亡率等进行了测定,采用ParsonsTR和TakahashiM营养动态模型和Tait沿岸海域能流分析模型对2个菲律宾蛤仔养殖池的养殖容量进行估算,扣除20%的日排水量导致的初级生产量损失,2种估算模型得到的养殖容量经校正后,池1为5.52t、7.1t,平均为6.31t;池2为3.60t、4.62t,平均为4.11t。两个花蛤养殖池的实际产量

  18. RISK CHARACTERIZATION OF A COASTAL ENVIRONMENT FACING A MINING AND INDUSTRIAL AREA IN SARDINIA (SULCIS-IGLESIENTE BY MEANS OF CLUSTER SAMPLING AND CONTAMINANTS RESEARCH ON EDIBLE FISH AND CLAMS

    Directory of Open Access Journals (Sweden)

    P.L. Piras

    2011-01-01

    Full Text Available On the basis of the results obtained from the analysis carried out on various environmental substrates (sediments, sea water and bio-indicators, it can be assumed that there has been a transfer of contaminants from sediments to edible “biota” in the Boi Cerbus lagoon (Sulcis-Iglesiente. It has also been verified that the benthic clams, in particular the Cerastoderma glaucum, is the species mainly affected by heavy metals contamination, in particular Lead, even if the role of Cadmium in the lagoon would need further investigation.

  19. Growth increment periodicity in the shell of the razor clam Ensis directus using stable isotopes as a method to validate age

    Directory of Open Access Journals (Sweden)

    J. F. M. F. Cardoso

    2013-07-01

    Full Text Available To evaluate the role of the razor clam Ensis directus in Dutch coastal waters, understanding its population dynamics is important. As such, the age structure of the population forms a key parameter. Accurate age determination in bivalve shells is not always straightforward due to the difficulty of interpreting externally visible growth lines. In the present paper, we aimed at validating the seasonality in growth line formation using visual techniques in combination with stable oxygen and carbon isotope analyses (δ18O and δ13C. High δ18O values in the shell coincided with growth marks on the external surface of the valve and in acetate peels of the shell's cross section. Most shell δ18O samples were assigned to the months from June to September. From November to March no samples were retrieved, indicating that the shell did not grow. The lowest reconstructed temperature (6.3 °C suggests that ~ 6 °C may be the threshold temperature for growth. Nevertheless, most of the reconstructed values fell above 14.5 °C, indicating that growth occurred mainly in the summer at relatively high temperatures. Shell δ13C profiles followed a more or less seasonal cycle, but no direct relationship could be made between δ13C values and annual growth lines. Although counting external annual growth lines led to a correct estimation of age and consequently of growth rates, we recommend analysing acetate peels of cross sections to support the distinction between annual lines and disturbance lines.

  20. Effect of permethrin, anthracene and mixture exposure on shell components, enzymatic activities and proteins status in the Mediterranean clam Venerupis decussata

    Energy Technology Data Exchange (ETDEWEB)

    Sellami, Badreddine, E-mail: sellamibadreddine@gmail.com [Laboratory of Environment Biomonitoring, Coastal Ecology Unit, Faculty of Sciences of Bizerta, University of Carthage, 7021 Zarzouna (Tunisia); Khazri, Abdelhafidh [Laboratory of Environment Biomonitoring, Coastal Ecology Unit, Faculty of Sciences of Bizerta, University of Carthage, 7021 Zarzouna (Tunisia); Mezni, Amine [Unit of Research 99/UR12-30, Department of Chemistry, Faculty of Sciences of Bizerte, 7021 Jarzouna (Tunisia); Louati, Héla; Dellali, Mohamed; Aissa, Patricia; Mahmoudi, Ezzeddine; Beyrem, Hamouda [Laboratory of Environment Biomonitoring, Coastal Ecology Unit, Faculty of Sciences of Bizerta, University of Carthage, 7021 Zarzouna (Tunisia); Sheehan, David, E-mail: d.sheehan@ucc.ie [Environmental Research Institute and Department of Biochemistry, University College Cork, Western Gateway Building, Western Road, Cork (Ireland)

    2015-01-15

    Highlights: • We assessed toxicity of anthracene, permethrin and their mixture on clams. • Tissue and stressor-dependent changes were observed in biochemical responses. • Permethrin induces phase transition from aragonite to calcite in shell structure. • Interactive effects were observed on digestive gland and gill biomarkers. • Both approaches give new vision to risk assessment of organic pollution. - Abstract: Anthracene (ANT) and permethrin (PER) are two of the more toxic compounds reaching the marine environment. This study aimed to determine the impact of these molecules on Venerupis decussata, an economically important species cultured on the Tunisian coast. Shell structure and its possible transformation upon exposure to the two contaminants were studied by X-ray diffraction and gravimetric analyses. Results revealed a phase transition in shell composition from aragonite to calcite after PER exposure, to a mixture of PER and ANT (Mix) but not for ANT alone. Catalase (CAT), superoxide dismutase (SOD) and glutathione transferase (GST) activities were determined in digestive gland and gills after exposure to ANT, PER and Mix to assess the impact of the contamination on the oxidative status of V. decussata. Enzyme activities increased in the digestive gland after PER treatment and in the gills after ANT treatment. PER exposure significantly reduced the levels of free thiols and increased levels of carbonylated proteins in the digestive gland, as compared to controls. In contrast, ANT exposure significantly reduced free thiols and increased the number of carbonylated proteins in the gills. Mix induced additive effects as measured by both enzymatic and proteomic approaches. The present study suggests that PER has a strong effect on shell structure; that PER and ANT exposure generate compound-dependent oxidative stress in the tissues of V. decussata and that a mixture of the two compounds has synergistic effects on biochemical response.

  1. Molecular characterization of two kazal-type serine proteinase inhibitor genes in the surf clam Mesodesma donacium exposed to Vibrio anguillarum.

    Science.gov (United States)

    Maldonado-Aguayo, Waleska; Núñez-Acuña, Gustavo; Valenzuela-Muñoz, Valentina; Chávez-Mardones, Jacqueline; Gallardo-Escárate, Cristian

    2013-06-01

    This study reports two kazal-type serine protease inhibitors (KPI) identified in a cDNA library from the surf clam Mesodesma donacium, and characterized through Rapid Amplification of cDNA Ends (RACE). The KPIs, denoted as MdSPI-1 and MdSPI-2, presented full sequences of 1139 bp and 781 bp respectively. MdSPI-1 had a 5'untranslated region (UTR) of 175 bp, a 3'UTR of 283 bp and an open reading frame (ORF) of 681 pb that encodes for 227 amino acids. MdSPI-2 showed a 5'UTR of 70 bp, a 3'UTR of 279 bp and an ORF of 432 bp that encodes for 144 amino acids. Both sequences presented two kazal-type tandem domains. Phylogenetic analysis of MdSPI-1 and MdSPI-2 shows a main clade composed by other bivalve species and closely related crustaceans. Real time PCR analysis showed that MdSPI-1 is mainly up-regulated in mantle, foot, gills and muscle tissues, while MdSPI-2 is expressed principally in foot tissue. Moreover, to evaluate the immune response of MdSPI-1 and MdSPI-2, infections with Vibrio anguillarum were performed. Herein, MdSPI-1 and MdSPI-2 transcription expression were significantly up-regulated at 2 and 8 h post-challenge. Our results suggest that MdSPI-1 and MdSPI-2 are important humoral factors of innate immunity in M. donacium.

  2. Prevalence and intensity of pathologies induced by the toxic dinoflagellate, Heterocapsa circularisquama, in the Mediterranean mussel, Mytilus galloprovincialis.

    Science.gov (United States)

    Basti, Leila; Endo, Makoto; Segawa, Susumu; Shumway, Sandra E; Tanaka, Yuji; Nagai, Satoshi

    2015-06-01

    The harmful dinoflagellate, Heterocapsa circularisquama, has been causing mass mortalities of bivalve molluscs in Japan, at relatively low cell densities. Although several studies have been conducted to determine the toxicity mechanisms, the specific cause of death is still unclear. In a previous study, in our laboratory, it was shown that H. circularisquama (10(3) cells ml(-1)) caused extensive cytotoxicity in the gills of short-neck clams, Ruditapes philippinarum. In the present study, Mediterranean mussels, Mytilus galloprovincialis, were exposed to H. circularisquama at four cell densities (5, 50, 500, 10(3) cells ml(-1)), three temperatures (15, 20, and 25°C), and three exposure durations (3, 24, and 48 h), and the pathologies in nine organs (gills, labial palps, mantle, hepatopancreas, stomach, intestines, exhalant siphon, adductor muscles, and foot) were assessed. Foot, adductor muscles, and exhalent siphons of mussels were not affected; however, 16 inflammatory (hemocytic infiltration and aggregation, diapedesis, hyperplasia, hypertrophy, edema, melanization, and firbrosis) and degenerative (thrombus, thrombosed edema, cilia matting and exfoliation, epithelial desquamation, atrophy, and necrosis) pathologies were identified in the gills, labial palps, mantle, hepatopancreas, stomach, and intestines. The total prevalence and total intensity of pathology in each individual mussel, and the prevalence and intensity of pathology in each organ increased significantly with increased cell density, exposure duration, and temperature. The prevalence of pathology was the highest in gills, followed by the prevalence in labial palps, mantle, stomach, and intestines. Pathology was least prevalent in the hepatopancreas. The intensity of pathology was the highest in the gills, followed by the labial palps and mantle, the stomach and intestines, and the hepatopancreas. This detailed quantitative histopathological study demonstrates that exposure to H. circularisquama

  3. Effects of particulate carbonaceous matter on the bioavailability of benzo[a]pyrene and 2,2‘,5,5‘-tetrachlorobiphenyl to the clam, Macoma balthica

    Science.gov (United States)

    McLeod, Pamela B.; van den Heuvel-Greve, Martine J.; Allen-King, Richelle M.; Luoma, Samuel N.; Luthy, Richard G.

    2004-01-01

    We investigated the bioavailability via diet of spiked benzo[a]pyrene (BaP) and 2,2‘,5,5‘-tetrachlorobiphenyl (PCB-52) from different carbonaceous (non-carbonate, carbon containing) particle types to clams (Macoma balthica) collected from San Francisco Bay. Our results reveal significant differences in absorption efficiency between compounds and among carbonaceous particle types. Absorption efficiency for PCB-52 was always greater than that for BaP bound to a given particle type. Among particles, absorption efficiency was highest from wood and diatoms and lowest from activated carbon. Large differences in absorption efficiency could not be simply explained by comparatively small differences in the particles' total organic carbon content. BaP and PCB-52 bound to activated carbon exhibited less than 2% absorption efficiency and were up to 60 times less available to clams than the same contaminants associated with other types of carbonaceous matter. These results suggest that variations in the amount and type of sediment particulate carbonaceous matter, whether naturally occurring or added as an amendment, will have a strong influence on the bioavailability of hydrophobic organic contaminants. This has important implications for environmental risk assessment, sediment management, and development of novel remediation techniques.

  4. Mg isotopes in biocarbonates: new insight into vital effects associated to echinoderms and bivalves calcification

    Science.gov (United States)

    Planchon, F.; Hermans, J.; Borremans, C.; Dubois, P.; Poulain, C.; Paulet, Y.; Andre, L.

    2007-12-01

    specific control of isotopic exchange by ACC. For bivalves, we considered one clam species (Ruditapes Philippinarum) from two different sampling sites in the gulf of Morbihan (Brittany, France). One site (Locmariaquer, Loc) is coastal and marine while the other (Le bono, BO) located upstream in the Auray river. For each site and specimen, we considered all reservoirs involved in the shell build-up: seawater, internal fluids with hemolymph (H) and extrapaleal fluid (EPF), soft tissues with mantle, muscle and remaining part (R) and finally aragonitic shells. Water d26Mg are -0.82 at Loc and -0.79 at BO and appear to be highly similar to internal fluids values (EPF and H), -0.6 for Loc and -0.8 for BO. The soft tissues with mean values of -2.7 (Mantle), -2.1 (Muscle), -2.8 (R) at both sites, show pronounced enrichments in the light isotopic fraction of Mg. The shells display the widest range of Mg isotopic signatures with -1.9 at Loc and -4.2 at BO suggesting that different routes of fractionation are acting. The shell signature at Loc similar to aragonitic coral (-1.9) suggests that moderate biological effects have influenced the shell composition at this site. In contrast, at BO, the very light signature of the shell suggests that a significant fraction of Mg has been internally recycled by the clam and used for the building of the shell.

  5. Seasonal Variation in the Biochemical Constituents, Percentage Edibility and Condition Index of the Estuarine Clam, Soletellina diphos (Linnaeus, 1771 (Mollusca: Bivalvia: Veneroida: Psammobiidae

    Directory of Open Access Journals (Sweden)

    Vishwajeet M. Lagade

    2015-01-01

    Full Text Available A variety of biochemical analyses and condition indices have been employed by various authors all over the world to assess the chemical and health index of bivalves. In order to understand the effect of seasonal climate change on the nutritive value and physiological fitness of an estuarine population of the psammobiid Soletellina diphos on the West coast of India. The present study was under-taken in order to determine the seasonal fluctuations of the biochemical constituents in different parts of the body and the percentage edibility and condition index. This study has shown that seasonality is related to significant alterations in the biochemical constituents, percentage edibility and condition index (pS. diphos. These changes could be due to the clam’s seasonal activities, particularly those related to its reproductive cycle. Higher values of the protein and lipid contents were recorded during the post-monsoon period, whereas maximum concentrations of glycogen were detected during the winter season. On the other hand, the lowest protein and glycogen contents were recorded during summer, while minimal lipid contents were observed during the winter season. The Percentage Edibility (PE and Condition Index (CI significantly fluctuated during the annual cycle, with maximum values occurring during the post-monsoon period (September-October 2008 and the lowest values during winter (November-December 2008. Therefore, it seems that the best nutritive season for S. diphos is in the post-monsoon period (September-October, when the highest values of its biochemical composition, percentage edibility and condition index occur. However, during the summer season (April-May, the lowest levels of the organic constituents, the percentage edibility and the condition index were recorded. Hence, that season is not ideal from the nutritive point of view. The study concludes that the physiological activity, the nutritive value and the meat quality of the clam S

  6. Numerical simulation on temperature and stress fields of CLAM steel TIG weld%CLAM钢TIG焊接头温度场和应力场数值模拟

    Institute of Scientific and Technical Information of China (English)

    雷玉成; 朱强; 尹莎; 巨新

    2011-01-01

    ANSYS thermal-structural coupling technology, Parametric Design Language, life-death element technique, and double ellipsoid heat source were applied togegher in the numerical simulation of temperature and stress fields on single layer welding and the single-sided double layer welding of CLAM steel TIG weld joints. Without considering phase change and only considering the effects of residual stress field, the stress field based on temperature field data was calculated. The results of simulation with that of experiment were compared. The numerical results of residual stress distribution are almost consistent with the experimental ones. On middle section of the surface, longitudinal stress is tensile stress near the weld zone, reaches the maximum in the fusion area, and turn to compressive stress away from weld zone.The transverse stress is small tensile stress. Residual stress of single-sided double-layer welding specimen is lower than that of single layer welding specimen.%运用ANSYS的热-结构耦合技术,采用APDL参数化语言及生死单元技术,以双椭球热源作为内热源,对CLAM钢TIG焊对接单层焊和单面双层焊的温度场进行了数值模拟.在不考虑焊接温度场对材料相变影响,而仅考虑对残余应力场影响的条件下,以温度场的计算数据为依据进行应力场的计算,并将应力场的模拟结果与试验结果进行比较.分析结果表明:焊件残余应力的实测值和模拟结果中残余应力分布比较吻合;在焊件截面上表面,纵向残余应力在近缝区为拉应力,且在熔合区附近达到最大,而远离焊缝处转变为压应力;横向残余应力比较小,且均为拉应力;单面双层焊件表面残余应力比单层焊件的残余应力小.

  7. Biodynamic modelling of the bioaccumulation of trace metals (Ag, As and Zn) by an infaunal estuarine invertebrate, the clam Scrobicularia plana

    Energy Technology Data Exchange (ETDEWEB)

    Kalman, J., E-mail: judit.kalman@uca.es [Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom); Smith, B.D. [Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom); Bury, N.R. [Division of Diabetes and Nutritional Science, King' s College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH (United Kingdom); Rainbow, P.S. [Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom)

    2014-09-15

    Highlights: • Biodynamic modelling is used to predict accumulation of Ag, As and Zn in S. plana. • Dissolved and sediment-associated metals contribute to total metal bioaccumulation. • Relative importance varies with water and sediment concentrations and geochemistries. - Abstract: Biodynamic modelling was used to investigate the uptake and accumulation of three trace metals (Ag, As, Zn) by the deposit feeding estuarine bivalve mollusc Scrobicularia plana. Radioactive labelling techniques were used to quantify the rates of trace metal uptake (and subsequent elimination) from water and sediment diet. The uptake rate constant from solution (±SE) was greatest for Ag (3.954 ± 0.375 l g{sup −1} d{sup −1}) followed by As (0.807 ± 0.129 l g{sup −1} d{sup −1}) and Zn (0.103 ± 0.016 l g{sup −1} d{sup −1}). Assimilation efficiencies from ingested sediment were 40.2 ± 1.3% (Ag), 31.7 ± 1.0% (Zn) and 25.3 ± 0.9% (As). Efflux rate constants after exposure to metals in the solution or sediment fell in the range of 0.014–0.060 d{sup −1}. By incorporating these physiological parameters into biodynamic models, our results showed that dissolved metal is the predominant source of accumulated Ag, As and Zn in S. plana, accounting for 66–99%, 50–97% and 52–98% of total accumulation of Ag, As and Zn, respectively, under different field exposure conditions. In general, model-predicted steady state concentrations of Ag, As and Zn matched well with those observed in clams collected in SW England estuaries. Our findings highlight the potential of biodynamic modelling to predict Ag, As and Zn accumulation in S. plana, taking into account specific dissolved and sediment concentrations of the metals at a particular field site, together with local water and sediment geochemistries.

  8. 几种生态因子对偏顶蛤浮游幼虫生长和发育的影响%Effects of several ecological factors on growth and development of planktonic larvae in clam Modiolus modiolus

    Institute of Scientific and Technical Information of China (English)

    宁军号; 胡盼; 宋坚; 常亚青; 张伟杰; 庞云龙; 杨力猛

    2014-01-01

    为了解偏顶蛤Modiolus modiolus最适培育条件,采用实验生态学方法研究了海水盐度、 pH和饵料对偏顶蛤浮游幼虫生长和发育的影响。结果表明:3种生态因子对偏顶蛤浮游幼虫的生长发育均有显著影响(P0·05)。%The effects of seawater salinity, pH and diet on growth and development of the planktonic larvae in clam Modiolus modiolus were investigated in order to explore the optimum culture conditions. It was found that growth and development of the planktonic larvae were significantly affected by the 3 ecological factors ( P0. 05).

  9. 魁蚶血细胞分类及其免疫功能的初步分析%Studies on the hemocytes types and their immunological functions in bloody clam (Scapharca broughtonii)

    Institute of Scientific and Technical Information of China (English)

    周丽青; 杨爱国; 王清; 刘志鸿; 吴彪; 田吉腾; 严加坤; 吕振明

    2013-01-01

    借助显微观察和鳗弧菌免疫刺激等手段,首次对魁蚶血细胞进行分类及免疫功能分析.魁蚶血细胞可分为3大类:红细胞、白细胞和血栓细胞,红细胞发育过程大致经历新生、成熟、衰老和死亡4个阶段.白细胞分为:嗜酸性、嗜中性、嗜碱性细胞,以及淋巴细胞和巨核细胞.嗜酸性、嗜中性、嗜碱性细胞和血栓细胞均参与血液的凝固;红细胞、白细胞均有吞噬病原菌能力,红细胞具有被动吞噬作用和免疫吸附作用,白细胞具有主动吞噬作用,嗜酸性和嗜中性细胞是吞噬病原菌的主体,嗜碱性细胞具有吞噬大颗粒异物的作用,魁蚶感染病原菌后白细胞增多并表现炎症.研究表明,魁蚶血细胞在应对外界的免疫刺激时,能作出系统免疫应答,且血细胞免疫分工明确,以抵御外界不良刺激.%It was the first time to study the types and immunological functions of blood cells in bloody clam (Scapharca broughtonii) by the means of microscopic observation and immunostimulation with pathogenic Vibrio anguillarum, and three types of hemocytes were recognized: red blood cells, white blood cells and thrombus cells. Red blood cells had four developmental states: freshmen, mature, aging and death. White blood cells were divided into acidophils, neutuophils, basophils, lymphocytes, and megalokaryocytic. Acidophils,neutuophils,basophils and thrombus cells were all involved in the blood coagulation. Both red blood cells and white blood cells had phagocytic function,red cells showed the passive phagocytic function and immune adherence function, while white cells showed the active phagocytic function. Acidophils and neutuophils cells were principal in phagocytizing pathogens, and basophils cells could be found phagocytizing large size foreign materials, an increase in the number of white cell and inflammation took place after the bloody clam was infected by pathogen. It was also the first time to show the

  10. First genotoxicity study of Paraná river water from Argentina using cells from the clam Corbicula fluminea (Veneroida Corbiculidae and Chinese hamster (Cricetulus griseus Rodentia, Cricetidae K1 cells in the comet assay

    Directory of Open Access Journals (Sweden)

    Jacqueline D. Caffetti

    2008-01-01

    Full Text Available High concentrations of xenobiotics from urban and industrial wastes have contributed to the contamination of many aquatic environments. We used the comet assay to evaluate the genotoxic potential of water collected from the River Paraná, which receives a great deal of waste, at three points (Puerto Piray, Eldorado and Montecarlo in the Misiones Province of Argentina. The in vivo comet assay used 40 freshwater clams (Corbicula fluminea while the in vitro comet assay used Chinese hamster (Cricetulus griseus K1 cell (CHO-K1 cultures with the mutagen ethyl methanesulfonate (EMS as the positive control and phosphate buffered saline (PBS as the negative control. Both assays showed statistically significant differences between the three sampling sites in relation to the negative control, the results of this preliminary study indicating that at these three sites water from the Paraná River presents genotoxic potential.

  11. Aspectos de biología reproductiva de la almeja de sifón Panopea globosa (Dall 1898 en el Golfo de California Aspects of reproductive biology of the geoduck clam Panopea globosa (Dall 1898 in the Gulf of California

    Directory of Open Access Journals (Sweden)

    Edna María Arambula-Pujol

    2008-08-01

    Full Text Available Este trabajo describe aspectos básicos de la biología reproductiva de la almeja de sifón Panopea globosa para una población de la porción centro-oriental del Golfo de California. Las almejas de sifón fueron colectadas mensualmente durante un periodo anual (octubre de 2004 a octubre de 2005 Se usó el índice gonadosomático y la técnica de crecimiento de ovocitos para determinar el periodo de reproducción. El periodo reproductivo se relacionó con la temperatura in situ además de la temperatura superficial del mar, tomada de la base de datos COADS. Las fases reproductivas fueron similares a las de las almejas de sifón presentes en Nueva Zelanda y Canadá. La gametogénesis inicia en otoño y el desove se presenta en enero-febrero (invierno cuando la temperatura está más fría (~18 ºC. Se encontró que P. globosa desova a temperaturas semejantes a las que lo hace P. zelandica en el Hemisferio Sur, pero que la estrategia reproductiva de P. globosa es más similar a la de P. abrupta (Hemisferio Norte, ya que el desove se presenta cuando la temperatura empieza a incrementarse. Los resultados del presente estudio pueden ser la base de futuras investigaciones sobre la biología, ecología y potencial pesquero de la almeja de sifón del Golfo de California.This paper describes basic aspect of reproductive biology of the geoduck clam Panopea globosa from a population in the east central Gulf of California. Geoduck clams were collected monthly for a year (October 2004-October 2005, The gonadosomatic index and ovocyte growing (oocyte diameters techniques were used to determine the spawning timing. Reproductive period was related with in situ temperature and seawater surface temperatures (SST from the Comprehensive Oceanic and Atmospheric Data Set. Reproduction phases were similar to other geoduck clams in New Zealand and Canada. Gametogenesis begins in autumn and spawning occurred between January and February (winter, when SST were at their

  12. 泥蚶血细胞的形态结构特征及部分免疫功能%Morphological, structural characteristics and phagocytic and enzymatic activities of haemocytes in blood clam Tegillarca granosa

    Institute of Scientific and Technical Information of China (English)

    朱泽闻; 徐立蒲; 吴信忠; 张振国; 吴刘记; 娄绘芳

    2011-01-01

    Light,electron microscopic and flow cytometer studies were conducted to characterize morphology and structure and phagocytosis of haemocytes in blood clam Tegillarca granosa. Based on cell size, and microstructure and granular types of cell, blood clam haemocytes were divided into red granulocyte (89. 67% ) ,basophil granulocyte (7. 05% ) and hyalinocyte (3. 28% ) respectively under light microscopy. The haemocyte densities in healthy blood clam haemolymph were assessed (3. 29 ±0. 82) × 106 cell/mL. Three kinds of haemocytes were respectively recognized by transmission electron microscope: granulocyte type Ⅰ , granulocyte type Ⅱ and agranulocyte. It was observed under scanning electron microscopy that haemocytes appear smooth-surface and some of them have knot-like projections in cell surface. APIZYM assays on enzymatic activities of 19 enzymes in haemolymph were performed and, of these, 13 and 10 enzymes were detected respectively in serum and cell. There were marked increases in the levels of ALP,ACP,ELIP(C8) and AGLA in serum and haemocytes after being stimulated by zymosan. Observation of phagocytosis in vitro revealed that there was phagocytic response in red granulocyte to zymosan and there was no significant phagocytic response in basophil granulocyte and hyalinocyte. It was observed that basophilic granulocyte accumulation and hyalinocyte adsorption after being stimulated by Aeromonas hydrophila. The study of environmental stress factors on phagocytosis activity revealed that the temperature and salinity have significant influence on phagocytosis activity. The phagocytosis percentage of blood clam reached the highest values with optimum growth temperature( 13 -30 ℃ )and salinity(20.0 -26.2) × 10-12.%利用光镜、透射电镜、扫描电镜及流式细胞仪技术对泥蚶血细胞形态结构以及吞噬活性进行了研究.根据细胞大小、形态结构、颗粒特点,光镜下可将血细胞区分为红色颗粒细胞(占89.67%)、嗜

  13. Use of Population Parameters in Examining Changes in the Status of the Short-Necked Clam Paphia undulata Born, 1778 (Mollusca, Pelecypoda: Veneridae in Coastal Waters of Southern Negros Occidental

    Directory of Open Access Journals (Sweden)

    Anabelle del Norte Campos

    2010-06-01

    Full Text Available Growth, recruitment, mortality and exploitation rate of the short-necked clam Paphia undulata (Born, 1778 were studied in southern Negros Occidental waters between August 2007 and July 2008 from length-frequency data derived from catches of divers, to be able to compare with earlier data derived and analyzed 13 years ago by Agasen et al. (1998. Both sets of data were analyzed using the FiSAT software (Gayanilo & Pauly, 1997. The asymptotic shell length (S¥ = 79 mm derived from the present data proved to be smaller compared to the earlier data (SL¥ = 81.5 mm due to the lack of bigger sizes in the present samples. The growth constant (K = 1.0 yr-1 was however comparable indicating it to be a more species-characteristic parameter. Two recruitment pulses for each study were derived and were found to be correlated with the spawning pattern in the species. The value of natural mortality (M = 1.57 yr-1 derived from bivalve literature, is deemed more appropriate compared to the earlier estimate (M = 2.89 yr-1 based on Pauly’s (1980 empirical equation developed for fish. Total mortality (Z values for both studies were comparable, but a higher level of fishing mortality (F = 4.61 yr-1 was estimated for the present data set, thus resulting likewise in a higher exploitation rate (E = 0.75. These, together with fishery information from an accompanying paper (Villarta & del Norte-Campos, 2010, not only validate the earlier findings of overexploitation due to lack of management, but reveal a worsening condition of the stock, most likely as a result of growth overfishing. Overexploitation can only be mitigated by imposing stringent restrictions in terms of the minimum size for exploitation (45 mm shell length and closed seasons during the spawning peak (August-November.

  14. Molecular characteristics and expression analysis of ScHsc70 cDNA in agamaki clam (Sinonovacula constricta)%缢蛏ScHsc70cDNA的分子特性和表达分析

    Institute of Scientific and Technical Information of China (English)

    冯冰冰; 牛东红; 钟玉民; 陈慧; 林国文; 李家乐

    2012-01-01

    Heat shock proteins consist of several families of highly conserved proteins that play an essential role in a number of cellular processes. Among the 70 kD family of heat shock proteins, heat shock cognate protein 70 kD (Hsc70) and inducible heat shock protein 70 kD (Hsp70) have been extensively studied in vertebrates and invertebrates. Several cDNAs encoding HSP70 have been described in molluscs, including the oyster (Crassostrea gigas), bay scallop (Argopecten irradians), Zhikong scallop (Chlamys farreri), mussel (Mytilus galloprovincialis), and Asiatic hard clam (Meretrix meretrix). Recent studies examining HSP70 expression in different species of mollusc have recognized the physiological and ecological importance of heat-shock gene expression in response to changing environments. We isolated an EST sequence with high homology with heat shock protein 70 gene from the cDNA library of Sinonovacula constricta. Then, the complete express sequence of this gene was obtained using PCR and 5'RACE. The cDNA of this gene was 2 335 bp, and consisted of a 76 bp 5' untranslated region (UTR), a 1 950 bp open reading frame (ORF) and a 309 bp 3' UTR. The translated protein consisted of 649 amino acids (70.89 kD)and its calculated isoelectric point was 5.28. Sequence analysis of the protein revealed that this gene contained three signature sequences of the heat shock protein 70 family (HSP70 family), two glycosylation sites and one ATP-GTP binding site. Four terapeptides of GGXP and a cytoplasm characteristic motif of EEVD were detected in the carboxyl terminal region of the deduced amino acid sequence. This HSP70 is a member of the HSC70 (constitutive genes) subfamily in the HSP70 family, and is designated as ScHsc70. Phylogenetic analysis suggested that the protein was most similar to those of 5. Constricta, Laternula elliptica, and M. Meretrix. Quantitative reverse transcriptase (qRT-PCR) analyses revealed that ScHsc70 mRNA was expressed constitutively in all the tissues

  15. Utilização do farelo de conchas de vôngole na adsorção de fósforo e como corretivo da acidez do solo Utilization of ground clam shells in the adsorption of phosphorus and for correction of soil acidity

    Directory of Open Access Journals (Sweden)

    Paola A. V. Lo Monaco

    2012-10-01

    Full Text Available Teve-se o objetivo de, com a realização deste trabalho, obter a curva de neutralização do pH de amostras dos horizontes A e B de um Latossolo Vermelho-Amarelo distrófico, utilizando-se de farelo de conchas de vôngole (Anomalocardia brasiliana; além disso, avaliar a capacidade de adsorção de fósforo, obtendo-se a isoterma de adsorção de melhor ajuste aos dados obtidos. Verificou-se que o farelo de concha de vôngole apresenta potencial para uso como corretivo de acidez do solo e que a dose recomendada para correção do pH do horizonte A do Latossolo Vermelho Amarelo distrófico estudado foi de 2,92 t ha-1, enquanto, para correção do horizonte B, foi de 3,35 t ha-1. O farelo de conchas de vôngole também apresentou alta capacidade de adsorção de fósforo, o que indica possibilidades de sua utilização em sistemas que visem à remoção deste elemento químico de águas residuárias. Os modelos de Langmuir e Freundlich ajustaram-se bem aos dados e podem ser utilizados para representar a isoterma de adsorção de fósforo.The objective of this study was to obtain the curve of pH neutralization for samples of the horizons A and B of a dystrophic Rhodic Haplustox soil using ground clam shells (Anomalocardia brasiliana, as well as assess the capacity of phosphorus adsorption to obtain the adsorption isotherm that best fit to the data obtained. It was found that the ground clam shells present potential to be used in soil acidity correction and that the recommended dose for pH correction of horizon A of the dystrophic Rhodic Haplustox studied was 2.92 t ha-1, while for correction of horizon B was 3.35 t ha-1. The ground clam shells also showed high adsorption capacity for phosphorus, which indicates possibilities of its use in systems targeting the removal of this chemical from wastewater. The Langmuir and Freundlich models fit well to the data and may be used to represent the adsorption isotherm.

  16. High Resolution Hydrologic Variability During ENSO Events in Modern, Mid-Holocene and Last Interglacial Periods Discerned from Coupled Isotope Time-Series in the Giant Clam T. gigas from the Raised Coral Reefs in Huon Pen., Papua New-Guinea

    Science.gov (United States)

    Kozmor, S.; Aharon, P.

    2015-12-01

    Understanding the past variability of El Niño-Southern Oscillation (ENSO) under contrasting climate states is of upmost importance because of its worldwide climate impact. The Western Pacific Warm Pool (WPWP) plays a dominant role in the development of ENSO but instrumental records do not go back far enough to determine the phase modes of the WPWP over intrannual and interannual intervals. Giant clams (T.gigas), associated with a flight of uplifted coral reef terraces on the Huon Peninsula, Papua New Guinea (PNG) along the Vitiaz Strait in the heart of the WPWP, are used in this study as highly resolved archives to investigate the intensity and frequency of ENSO events during modern, mid-Holocene and the Last Interglacial. Time-series analyses of stable oxygen and carbon isotopes at subweekly resolution, coupled with monthly resolution of AMS Δ14C determinations, has allowed documentation of hydrological changes occurring during ENSO events. Time series from modern T. gigas that overlap with instrumental rainfall and ENSO records, indicate that an El Niño event exhibits an increase of 5‰ above average in Δ14C accompanied by positive δ18O and δ13C excursions while during a La Niña event Δ14C falls 3‰ below average accompanied by negative δ18O and δ13C excursions. We show numerically that phase transitions in the three isotope proxies within the ENSO frequency band are compatible with excess seawater evaporation during severe El-Niño droughts and intensive freshwater discharge draining the Late Pleistocene coral terraces into the coastal reef environment during La-Niña wet events. The combined study of stable isotopes and Δ14C demonstrates that giant clams show high potential to serve as robust archives of seasonal and interannual hydrologic variability accompanying ENSO events. We applied modern δ18O threshold limits to fossil giant clams from the mid-Holocene (5.4 ka) and Last Interglacial (134 ka). The mid-Holocene time-series show a lower

  17. Burrowing criteria and burrowing mode adjustment in bivalves to varying geoenvironmental conditions in intertidal flats and beaches.

    Directory of Open Access Journals (Sweden)

    Shinji Sassa

    Full Text Available The response of bivalves to their abiotic environment has been widely studied in relation to hydroenvironmental conditions, sediment types and sediment grain sizes. However, the possible role of varying geoenvironmental conditions in their habitats remains poorly understood. Here, we show that the hardness of the surficial intertidal sediments varies by a factor of 20-50 due to suction development and suction-induced void state changes in the essentially saturated states of intertidal flats and beaches. We investigated the response of two species of bivalves, Ruditapes philippinarum and Donax semigranosus, in the laboratory by simulating such prevailing geoenvironmental conditions in the field. The experimental results demonstrate that the bivalve responses depended strongly on the varying geoenvironmental conditions. Notably, both bivalves consistently shifted their burrowing modes, reducing the burrowing angle and burial depth, in response to increasing hardness, to compensate for the excessive energy required for burrowing, as explained by a proposed conceptual model. This burrowing mode adjustment was accompanied by two burrowing criteria below or above which the bivalves accomplished vertical burrowing or failed to burrow, respectively. The suitable and fatal conditions differed markedly with species and shell lengths. The acute sensitivities of the observed bivalve responses to geoenvironmental changes revealed two distinctive mechanisms accounting for the adult-juvenile spatial distributions of Ruditapes philippinarum and the behavioral adaptation to a rapidly changing geoenvironment of Donax semigranosus. The present results may provide a rational basis by which to understand the ensuing, and to predict future, bivalve responses to geoenvironmental changes in intertidal zones.

  18. 九种现代双壳类壳体物相组成的对比研究%Comparison Study on the Shell Mineralogy of 9 Species of Modern Bivalves Living in Yellow Sea

    Institute of Scientific and Technical Information of China (English)

    范德江; 刘升发; 张爱滨; 于子山; 王文正

    2005-01-01

    利用X射线衍射分析技术,对黄东海常见的9种现代双壳类壳体进行了物相分析,结果表明这些双壳类壳体分别属于三种类型,即文石质壳、方解石质壳、文石+方解石混合质壳.其中,菲律宾蛤仔(Ruditapes philippinarum)、中国蛤蜊(Mactra chinensis)、四角蛤蜊(Mactra veneriformis)、薄片镜蛤(Dosinia laminata)、毛蚶(Scapharca subcrenuzta)属于文石质壳,长牡蛎(Crassostrea gigas)、中国不等蛤(Anomia chinensis)、海湾扇贝(Argopecten irradieus)属于方解石质壳,紫贻贝(Mytilus edulis)属于文石+方解石质的混合质壳;双壳类壳体物相组成与其生活方式有着一定的联系,营底栖埋入式生活者趋于形成文石质壳,底栖固着生活方式者趋于形成方解石质壳或混合质壳;不同大小的菲律宾蛤仔(Ruditapes philippinarum)的物相组成上几乎没有差别,表明其壳体物相组成不受生命效应的影响.

  19. P-glycoprotein and its inducible expression in three bivalve species after exposure to Prorocentrum lima.

    Science.gov (United States)

    Huang, Lu; Liu, Su-Li; Zheng, Jian-Wei; Li, Hong-Ye; Liu, Jie-Sheng; Yang, Wei-Dong

    2015-12-01

    P-glycoprotein (P-gp or ABCB1) belongs to the family of ATP-binding cassette (ABC) transporters responsible for multixenobiotic resistance (MXR) in aquatic organisms. To provide more information of P-gp in shellfish, in this study, complete cDNA of P-gp in three bivalve species including Ruditapes philippinarum, Scapharca subcrenata and Tegillarca granosa were cloned and its expressions in gill, digestive gland, adductor muscle and mantle of the three bivalves were detected after exposure to Prorocentrum lima, a toxogenic dinoflagellate. The complete sequences of R. philippinarum, S. subcrenata and T. granosa P-gp showed high homology with MDR/P-gp/ABCB proteins from other species, having a typical sequence organization as full transporters from the ABCB family. Phylogenetic analyses revealed that the amino acid sequences of P-gp from S. subcrenata and T. granosa had a closest relationship, forming an independent branch, then grouping into the other branch with Mytilus californianus, Mytilus galloprovincialis and Crassostrea gigas. However, P-gp sequences from R. philippinarum were more similar to the homologs from the more distantly related Aplysia californica than to homologs from S. subcrenata and T. granosa, suggesting that bivalves P-gp might have different paralogs. P-glycoprotein expressed in all detected tissues but there were large differences between them. After exposure to P. lima, the expression of P-gp changed in the four tissues in varying degrees within the same species and between different species, but the changes in mRNA and protein level were not always synchronous.

  20. 帘蛤科贝类rDNA内转录间隔区序列的研究%Study on Sequences of Ribosomal DNA Internal Transcribed Spacers of Clams Belonging to the Veneridae Family (Mollusca: Bivalvia)

    Institute of Scientific and Technical Information of China (English)

    程汉良; 夏德全; 吴婷婷; 孟学平; 吉红九; 董志国

    2006-01-01

    spacer (ITS1 and ITS2) regions of the ribosomal DNA from four species,Meretrix meretrix L., Cyclina sinensis G., Mercenaria mercenaria L., and Protothaca jedoensis L., belonging to the family Veneridae were amplified by PCR and sequenced. The size of the ITS 1 PCR amplification product ranged from 663 bp to 978 bp,with GC contents ranging from 60.78% to 64.97%. The size of the ITS1 sequence ranged from 585 bp to 900 bp, which is the largest range reported thus far in bivalve species, with GC contents ranging from 61.03% to 65.62%. The size of the ITS2 PCR amplification product ranged from 513 bp to 644 bp, with GC contents ranging from 61.29% to 62.73%. The size of the ITS2sequence ranged from 281 bp to 412 bp, with GC contents ranging from 65.21% to 67.87%. Extensive sequence variation and obvious length polymorphisms were noted for both regions in these species, and sequence similarity of ITS2 was higher than that of ITS1 across species. The complete sequences of 5.8S ribosomal RNA gene were obtained by assembling ITS1 and ITS2 sequences,and the sequence length in all species was 157 bp. The phylogenetic tree of Veneridae clams was reconstructed using ITS2-containing partial sequences of both 5.8S and 28S ribosomal DNA as markers and the corresponding sequence information in Arctica islandica as the outgroup. Tree topologies indicated that P. jedoensis shared a close relationship with M. mercenaria and C.sinensis, a distant relationship with other species.

  1. The use of multivariate analysis to link sediment contamination and toxicity data to establish sediment quality guidelines: an example in the Gulf of Cadiz (Spain); El uso del analisis multivariante en la union de datos de toxicidad y contaminacion para establecer guias de calidad de sedimento: Un ejemplo en la Bahia de Cadiz (Espana)

    Energy Technology Data Exchange (ETDEWEB)

    Del Valls, T. Angel; Forja, Jesus M [Departamento de Quimica Fisica, Facultad de Ciencias del Mar, Universidad de Cadiz, Cadiz, (Spain); Gomez-Parra, Abelardo [Instituto de Ciencias Marinas de Andalucia, CSIC, Puerto Real, Cadiz, (Spain)

    1998-03-01

    To evaluate marine sediment quality in the Gulf of Cadiz, chemical concentration and toxicity test endpoints from sediments were linked using multivariate analysis. Sediment samples were collected synoptically at seven stations in two littoral ecosystems of the Gulf of Cadiz (five in the Bay of Cadiz and two in the salt marsh of the Barbate River), and subjected to six separate, replicated sediment toxicity tests and comprehensive sediment chemistry analyses. The toxic effects of sediments were tested using three operational sediment phases: whole sediment, using the estuarine amphipod Microdeutopus gryllotalpa (10 d static: survival) and the estuarine clam Ruditapes philippinaru (48 h static: survival) and of the marine fish Sparus aurata (48 h static. Survival); and interstitial water, using populations of the estuarine rotifer Brachionus Plicatilis (7 d static: Population decline) and of the marine bacteria Photobacterium phosphoreum (Microtox ). To evaluate the levels of contamination, the concentrations in the sediments of organic carbon, 14 trace metals (Fe, Mn, Cu, Zn, Pb, Cd, Ag, Hg, As, Sn, V, Ni, Co and Cr) and the surfactant linear alkylbenzenesulphonate (LAS) were measured. The results of the toxicity tests were compared in a dose-response relationship between sites, demonstrating a general agreement between the toxicity values determined by all the tests, except in the case of interstitial water toxicity (principally due to toxic mixtures of trace metals). Data derived from sediment chemistry and bioassays were assembled by multivariate statistical techniques (PCA and factor analysis), showing that the two data types could be represented by only five factors corresponding to five overlapping chemical-biological effect relations. Positive prevalence of these factors in the cases studied was used to establish those ranges in chemical concentrations associated with adverse effects. The sediment quality guidelines, in terms of concentrations at or below

  2. Damages of coral reef ecosystem by the giant clam excavation--- a case study on North Reef of Xisha Islands%砗磲采挖对珊瑚礁生态系统的破坏--以西沙北礁为例

    Institute of Scientific and Technical Information of China (English)

    李元超; 韩有定; 陈石泉; 谢海群; 陈孝; 周治东

    2015-01-01

    The variations of coral reefs was compared before and after the excavation of giant clams on North Reef of Xisha Islands to illustrate the destructions on the coral reef ecosystem.The results showed that 29 coral species dis-appeared on the reef flat of North Reef in 2014 compared to that in 2012.Dominant species evolved from previous Acropora sp.to Montipora digitata.The diversity index of corals became low in the reef flat.Although North Reef maintained 52.83% of mean coral coverage,around 10% reduction in coral coverage was found in 2014 compared with that in 2012.Particularly,the coral coverage was reduced as much as 20% with bleaching corals at station 2. The findings suggest that North Reef,especially the reef flat,has suffered severe damages.As results,the numbers of coral species were deceased and the community structure altered besides the deceased of species diversity and coral coverage and increased of coral mortality.It is considered that the coral reef degradation on North Reef is re-sulted from the illegal excavation of giant clams,which is an important factor destroyed and threatened the health of coral reef ecosystem in the flat.%以西沙群岛北礁为例,通过对比采挖砗磲前后的数据,来说明该活动对珊瑚礁生态系统的破坏.2012~2014年间北礁礁坪上的造礁石珊瑚种类数量变动较大,减少了29种;优势种由之前的鹿角珊瑚(Acropora sp.)变为现在的指状蔷薇珊瑚(Montipora digitata);礁坪的物种多样性指数也处于较低的水平.虽然当前北礁的珊瑚覆盖率为52.83%,但是相比2012年降低了大约10%,尤其是2号站位,珊瑚覆盖率降低了约20%.同时2号站位出现了珊瑚白化死亡的现象.调查结果表明,北礁的珊瑚礁生态系统,尤其是礁坪上的珊瑚礁生态系统已经受到严重的破坏,珊瑚种类减少、群落结构改变、物种多样性降低、覆盖率下降、死亡率提高.通过分析

  3. 鲜活水产品及其制品中硼含量的测定%Determination of Boron in Fresh and Processed Aquatic Products

    Institute of Scientific and Technical Information of China (English)

    沈康俊; 蔡友琼; 李冰; 于慧娟

    2012-01-01

    采用电感耦合等离子体质谱法测定26种鲜活水产品及其制品中硼的含量。结果表明,南极磷虾、泥蚶、牡蛎和菲律宾蛤仔中的硼含量最高(1.183~4.240mg/kg),大菱鲆中的硼含量最低(0.006mg/kg)。按生存环境划分,鱼类样品中硼含量为海捕产品〉淡水养殖产品〉海水养殖产品;虾类样品中硼含量为海捕产品〉海水养殖产品〉淡水养殖产品;蟹类样品中硼含量为海水养殖产品〉淡水养殖产品。水产制品中的硼含量在0.458~0.849mg/kg之间。通过评估认为,大部分水产品及其制品中的硼含量均在0.900mg/kg以下,可以放心食用,但南极磷虾、牡蛎、泥蚶和菲律宾蛤仔硼含量较高,为保障安全,建议少食为宜。%Twenty-six samples of fresh and processed aquatic products from different species were determined for boron content by inductively coupled plasma mass spectrometry.Boron content in Antarctic krill,Ark shell,oyster and Ruditapes philippinarum(1.183–4.240 mg/kg) were much higher than other samples,while turbot had the lowest boron content(0.006 mg/kg).In decreasing order of boron content,different living environments were wild marine,farmed freshwater and farmed marine for fish,wild marine,farmed marine and farmed freshwater for shrimp,and farmed marine and farmed freshwater for crab.Boron content in aquatic products ranged from 0.458 to 0.849 mg/kg,lower than 0.900 mg/kg.We assessed most of the tested fresh and processed aquatic products to be safe to eat.However,Antarctic krill,oyster,Ark shell and Ruditapes philippinarum should be eaten less for safety purpose due to higher boron content.

  4. 浙江近岸海域贝类中重金属和贝毒污染状况研究%Contamination status of heavy metals and shellfish poisoning in the shellfish samples of Zhejiang coastal areas

    Institute of Scientific and Technical Information of China (English)

    母清林; 王晓华; 佘运勇; 邹伟明; 王剑; 王艳华

    2013-01-01

      在浙江近岸海域采集了青蛤(Cyclina sinensis)、毛蚶(Scapharca subcrenata)、厚壳贻贝(Mytilus coruscus)、缢蛏(Sinonovacula constricta)、泥螺(Bullacta exarata)、菲律宾蛤仔(Ruditapes philippi-narum)、文蛤(Meretrix meretrix)、僧帽牡蛎(Ostrea cucullata)和栉孔扇贝(Chlamys farreri)共9种贝类计29份样品,检测其中重金属汞、砷、铜、铅、锌、镉以及麻痹性贝毒和腹泻性贝毒。结果表明,瑞安毛蚶、瑞安栉孔扇贝中有麻痹性贝类毒素检出,嵊泗文蛤、毛蚶和乐清牡蛎中存在重金属超标的情况;牡蛎对汞、铜、锌、镉有较强的富集能力。%Twenty nine samples belonging to 9 species of shellfishes including Cyclina sinensis, Scapharca sub-crenat, Mytilus coruscus, Sinonovacula constricta, Bullacta exarata, Ruditapes philippinarum, Meretrix meretrix, Ostrea cucullata and Chlamys farreri were collected from coastal waters of Zhejiang. Heavy metals including mercury, arsenic, copper, lead, zinc, cadmium and paralytic shellfish poisoning toxins, diarrhetic shellfish poisoning toxins were detected. Paralytic shellfish poisoning toxins were detected in RuiAn S. subcrenata and Ruian C. farreri. Content of heavy metals in ShengSi M. meretrix, ShengSi S. subcrenata and LeQing O. cucullata exceed the stan-dard, and oysters have high capability in enrichment of heavy metals such as mercury, copper, zinc and cadmium.

  5. 基于鳃的 microRNA 转录组研究中国蛤蜊对重金属镉的响应%Identification and differential expression of gill microRNA in the Chinese surf clam (Mactra chinensis)with Cd2+ exposure

    Institute of Scientific and Technical Information of China (English)

    张晶晶; 李宏俊; 秦艳杰; 刘敏; 叶晟

    2016-01-01

    中国蛤蜊(Mactra chinensis )是一种重要的经济贝类,分布于我国的辽宁和山东。近年来,生境恶化和过度捕捞导致我国蛤蜊资源量减少。我们利用 Illumina Hiseq-2500平台对中国蛤蜊鳃的 microRNA 转录组进行测序,运用差异表达寻找对镉刺激有响应的功能 microRNA。结果显示对照组获得了14415256条 clean reads,实验组获得了15570111条 clean reads。在这些 reads 中一共存在14584077小 RNA,包括1898035条 unique 小 RNA,其中对照组和实验组共有187859条 unique 小 RNA。两个组的小 RNA 文库的片段长度分布是相似的,大部分小 RNA 长度分布在26~27 nt。在对照组文库中最丰富的片段长度是27 nt,其次是28 nt、26 nt 和23 nt。在实验组文库中,数量最丰富的片段长度是26 nt,其次是27 nt、28 nt 和23 nt。经过对序列前体以及结构特征的分析,发现这两个组中一共有50个 microRNA,其中已知的是38个,新发现的是12个。对照组和实验组 microRNA 含量最丰富的片段长度是23 nt。通过差异表达分析,5个 microRNA 基因具有显著性差异且从对照组到实验组的表达量是上调的,其余45个没有显著性的差异。把这50个序列与中国蛤蜊转录组进行比对,一共找到了542个靶基因。5个具有表达差异的基因一共比对到11个靶基因。把这11个靶基因与 NCBI 数据库比对,4个靶基因在 COG 中得到注释,1个靶基因在 GO 中得到注释,6个靶基因在 KEGG 中得到注释,11个靶基因在 nr 数据库中得到注释,注释到的基因有泛素蛋白连接酶 E3,Wnt 信号通路,G 蛋白信号调控等。%The Chinese surf clam (Mactra chinensis )is an economically important clam,distributed in Lia-oning Province and Shandong Province.In recently years,because of coastal environmental deterioration and overfishing,the natural population of M.chinensis have considerably declined

  6. Molecular Detection of the Three Major Pathogenic Vibrio Species from Seafood Products and Sediments in Tunisia Using Real-Time PCR.

    Science.gov (United States)

    Gdoura, Morsi; Sellami, Hanen; Nasfi, Hanen; Trabelsi, Rahma; Mansour, Sabeur; Attia, Touraya; Nsaibia, Siwar; Vallaeys, Tatiana; Gdoura, Radhouane; Siala, Mariam

    2016-12-01

    Vibrio spp. have emerged as a serious threat to human health worldwide. V. parahaemolyticus , V. cholerae , and V. vulnificus pose a considerable public health risk in Tunisia because they cause sporadic and epidemic foodborne infections associated with the consumption of raw or undercooked contaminated seafood. More recently, toxR-positive V. alginolyticus was also reported to be a potential source of contaminated seafood. A total of 247 samples, including 113 fishes ( Labrus viridis , Penaeus kerathurus , Diplodus annularis , Diplodus sparaillon , Scorparna porcus , Sarpa salpa , Dentex dentex , Scorparna scrofa , Sardinella aurita , Trachurus trachurus , Synodus saurus , Pagellus erythrinus , and Metapenaeus monoceros ), 83 clams ( Ruditapes decussatus species), 30 seawater samples, and 21 sediment samples were analyzed using traditional culture methods (ISO/TS 21872-1; International Organization for Standardization 2007) and a conventional PCR method for Vibrio spp.

  7. Characterization of pathogenic vibrios isolated from bivalve hatcheries in Galicia, NW Atlantic coast of Spain. Description of Vibrio tubiashii subsp. europaeus [corrected] subsp. nov.

    Science.gov (United States)

    Prado, Susana; Dubert, Javier; Barja, Juan L

    2015-02-01

    The taxonomic position of the bivalve pathogen PP-638 was studied together with five similar isolates. The strains were isolated from flat oyster (Ostrea edulis) and Manila clam (Venerupis philippinarum) cultures during outbreaks of disease in two shellfish hatcheries (Galicia, NW Spain). The pathogenicity, previously established for PP-638, was demonstrated with all isolates and for several bivalve species, including the original hosts. On the basis of phenotypic characterization and 16S rRNA gene sequences, a tight group was defined within the genus Vibrio. Multilocus sequence analysis (MLSA) based on concatenated sequences of the 16S rRNA gene and the five housekeeping genes recA, rpoA, pyrH, gyrB and ftsZ revealed that these strains form a cluster within the Orientalis clade, close to the species Vibrio tubiashii. The results of MLSA, the DDH rate and the phenotypic differences with the type strain of V. tubiashii supported the differentiation of the Galician isolates as a new subspecies within V. tubiashii, for which the name V. tubiashii subsp. europaeus [corrected] subsp. nov. is proposed (type strain PP-638(T)=CECT 8136(T)=DSM 7349(T)) The emended description of V. tubiashii is included. The pathogenicity assays widen the host range of V. tubiashii to add two unreported species, Venerupis decussata and Donax trunculus, and the described as relatively resistant species V. philippinarum.

  8. Allozymic variation in the clam genus Eurhomalea (Bivalvia: Veneriidae along southern South American coast Variación alozímica en el género de almejas Eurhomalea (Bivalvia: Veneriidae a lo largo de la costa sur de Sudamérica

    Directory of Open Access Journals (Sweden)

    M.H GALLARDO

    2003-09-01

    Full Text Available The correspondence between allozymic variation and specific differentiation was studied in four populations corresponding to the three nominal, allopatric species of clam genus Eurhomalea (E. rufa, E. lenticularis, E. exalbida described for southern South America. Allozyme variation scored in 12 loci was high as indicated by heterozygosity levels (15.8-20.7 % and by the presence of only three monomorphic loci (Hk-2, Icd-2, and Xdh-1. These high estimates of allelic variability were influenced by the low levels of interspecific genetic similarity (I = 0.64 and for the high conspecific values of genetic identity observed. The high estimates of substructuring found at the species level (F ST = 0.39 contrasted with the low differentiation (F ST = 0.027 and high migration rate (Nm = 9 existing among conspecific samples. Diagnostic allele fixation coinciding with specific recognition was recorded at locus Hk-1 whereas nearly-fixed differences at loci (Adh, alpha-Gpd, Icd-1, Ldh, Odh, Pgm-3 differed sharply in frequency among species. The Wagner procedure and the neighbor-joining algorithm produced a similar tree topology highly related to the geographic distance and to their taxonomic recognition. The lack of coincidence between patterns of allozymic variation and the two distinctive shell morphs (flat and globoid occurring in E. exalbida from Ushuaia bay do not support their taxonomic recognition.Se estudió la correspondencia entre la variación bioquímica y la diferenciación específica en cuatro poblaciones correspondientes a las tres especies nominales y alopátricas en las almejas del género Eurhomalea (E. rufa, E. lenticularis, E. exalbida descritas para la zona sur de Sudamérica. La variación alozímica registrada en 12 loci fue alta como lo indican los altos niveles de heterocigosidad (15,8-20,7 % y por la presencia de solo tres loci monomórficos (Hk-2, Icd-2 y Xdh-1. Esta alta estimación de variabilidad alélica influyó en los bajos

  9. Metapopulation Dynamics of the Softshell Clam, Mya arenaria

    Science.gov (United States)

    2008-06-01

    aragonitic tmaritte bivalve shells. Geochetn. Geophys. Geosyst. 6. Q05009. Solow and S. Thorrold were helpful with data interpretation. We Hatmer, P.A... Roberts . D.. Schnitker, D., Baldauf, J., Desprairies, A., Hoinrighausen, R., Huddlestun, P., Keene, J., Kaltenback, A., Krumsick, K., Morton, A

  10. Photosymbiotic Giant Clams are Transformers of Solar Flux

    Science.gov (United States)

    2014-01-01

    shell adductor muscle was severed from one valve , and then a 8 mm diameter biopsy of the complete thickness of the mantle margin (2–4 mm thick...light as a butterfly mating signal. Nature 423, 31–32. (doi:10.1038/423031a) 6. Shashar N, Borst DT, Ament SA, Saidel WM, Smolowitz RM, Hanlon RT. 2001

  11. Assessment of the toxicity of sediment and seawater polluted by the Prestige fuel spill using bioassays with clams (Venerupis pullastra, Tappes decussatus and Venerupis rhomboideus) and the microalga Skeletonema costatum; Evaluacion de la toxicidad de sedimento y agua de mar contaminados por el vertido de fuel del Prestige, mediante el uso de bioensayos con las almejas Venerupis pullastra, Tappes decussatus y Venerupis rhomboideus y la microalga Skeletonema costatum

    Energy Technology Data Exchange (ETDEWEB)

    Marino-Balsa, J.C.; Perez, P.; Estevez-Blanco, P.; Saco-Alvarez, L.; Fernandez, E.; Beiras, R. [Laboratorio de Ecologia Marina LEM, Facultad de Ciencias, Universidad de Vigo, Galicia (Spain)

    2003-03-15

    In this study we present the early monitoring of the pollution caused by the accident of the Prestige tanker off the Galician coast. To evaluate the toxicity of sediment and water exposed to fuel, three kinds of bioassays were carried out using juvenile clams, clam embryos and microalgae. Firstly, the burrowing behavior of Venerupis pullastra and Tappes decussatus in the sediment collected from two beaches of similar characteristics but different pollution conditions, was studied over 24 h. No significant differences were observed between the two sediments. Secondly, embryogenesis success of Venerupis rhomboideus was recorded after incubation in seawater and elutriates obtained from affected areas. In this case, fuel-polluted seawater showed a marked inhibition of embryogenesis, while sediment elutriates showed moderate toxicity. Parallel bioassays with the diatom Skeletonema costatum were carried out using sediment elutriates and filtered seawater from the sampling sites. The response variable measured was the maximum quantum yield of photosynthesis ({phi}{sub p}o) using a Fast Repetition Rate Fluorometer (FRRF). In the first sampling, significant differences were found in the response of S. costatum cultured in the elutriates as compared to the control after 5 h exposure. The results corresponding to the second sampling showed statistically significant lower values of {phi}{sub p}o in the culture incubated in M2 water as compared with the control, indicating that the water-accommodated fraction of fuel at this site was the most toxic. [Spanish] En este estudio presentamos los primeros resultados obtenidos del control de la contaminacion producida por el accidente del petrolero Prestige en la costa de Galicia. Para evaluar la toxicidad del agua y el sedimento expuestos al fuel, se realizaron tres tipos de bioensayos: usando almejas juveniles, embriones de almeja y una microalga. En los primeros, se evaluo el comportamiento de enterramiento de Venerupis pullastra y

  12. 胶州湾双壳类壳体中的Ca,Mg,Mn,Sr元素组成及影响因素%Components of Ca, Mg, Mn and Sr in Bivalve Shells from Jiaozhou Bay and Their Influence Factors

    Institute of Scientific and Technical Information of China (English)

    张爱滨; 刘升发; 范德江; 颜文涛

    2006-01-01

    探讨影响双壳类元素组成的可能因素,从胶州湾沿岸不同取样点采集黄海近海常见的菲律宾蛤仔(Ruditapes philippinarum)、褶牡蛎(Oystrea denselamellosa)和紫贻贝(Mytilus galloprovincialis),分别测量了3种壳体的矿物物相类型和壳体中的Ca,Mg,Mn,Sr元素组成.研究表明:3种壳体分别属于文石质、方解石质和混合质壳;Ca,Mn元素含量在菲律宾蛤仔、褶牡蛎和紫贻贝壳体中没有差别,而Mg元素含量在菲律宾蛤仔壳体中含量较低,在褶牡蛎壳体和紫贻贝壳体中含量较高,Sr元素恰好与Mg元素相反.双壳类壳体中元素组成主要受壳体矿物物相类型的制约,而与水体环境要素之间的关系弱.

  13. Polycyclic Aromatic Hydrocarbons in Sediments and Bivalves on the Pacific Coast of Japan: Influence of Tsunami and Fire

    Science.gov (United States)

    Onozato, Mayu; Nishigaki, Atsuko; Okoshi, Kenji

    2016-01-01

    Surface sediments and at least one edible bivalve species (Ruditapes philippinarum, Mytilus galloprovincialis, and Crassostrea gigas) were collected from each of seven intertidal sites in Japan in 2013. The sites had experienced varying levels of tsunami and fire disturbance following the major earthquake of 2011. Eight polycyclic aromatic hydrocarbons (PAHs) were identified and analyzed by gas chromatography–mass spectrometry. Total sediment PAH concentration (CT), the sum of the average concentrations of the eight PAHs, was 21–1447 μg kg-1-dry. Relative to the average level of one type of PAH in sediments collected around Japan in 2002 (benzo[a]pyrene = 21 μg kg-1-dry), five of the seven sites showed concentrations significantly lower than this average in 2013. The CTs for the three bivalves (134–450 μg kg-1-dry) were within the range of the previous reports (2.2–5335 μg kg-1-dry). The data suggest that the natural disaster did not increase PAH concentrations or affect the distribution within sediment or bivalves in Tohoku district. Although PAH concentrations at the sites pose no risk to human health, the findings highlight that the observed PAH levels derive from pre- rather than post-quake processes. PMID:27232189

  14. Polycyclic Aromatic Hydrocarbons in Sediments and Bivalves on the Pacific Coast of Japan: Influence of Tsunami and Fire.

    Directory of Open Access Journals (Sweden)

    Mayu Onozato

    Full Text Available Surface sediments and at least one edible bivalve species (Ruditapes philippinarum, Mytilus galloprovincialis, and Crassostrea gigas were collected from each of seven intertidal sites in Japan in 2013. The sites had experienced varying levels of tsunami and fire disturbance following the major earthquake of 2011. Eight polycyclic aromatic hydrocarbons (PAHs were identified and analyzed by gas chromatography-mass spectrometry. Total sediment PAH concentration (CT, the sum of the average concentrations of the eight PAHs, was 21-1447 μg kg-1-dry. Relative to the average level of one type of PAH in sediments collected around Japan in 2002 (benzo[a]pyrene = 21 μg kg-1-dry, five of the seven sites showed concentrations significantly lower than this average in 2013. The CTs for the three bivalves (134-450 μg kg-1-dry were within the range of the previous reports (2.2-5335 μg kg-1-dry. The data suggest that the natural disaster did not increase PAH concentrations or affect the distribution within sediment or bivalves in Tohoku district. Although PAH concentrations at the sites pose no risk to human health, the findings highlight that the observed PAH levels derive from pre- rather than post-quake processes.

  15. Effects of the different diets on numbers, hatching rate and the Octopus vulgaris in spawning size of newly hatching larvae%不同饵料对真蛸亲体产罗同量、受精卵孵化率及初孵幼体大小的影响

    Institute of Scientific and Technical Information of China (English)

    刘兆胜; 刘永胜; 郑小东; 曲海波

    2011-01-01

    The parent Octopus vulgaris in spawning and protecting period were fed on Meretrix meretrix, Ruditapes philippinarum, Sinonovacula constrzct and Sebastodes fuscescens, respectively. The effects of those diets on food intake, spawning numbers, hatching rate of eggs as well as the size of newly hatching larvae were investigated. The results showed that average food intake per individual parent per day was such an order, M.meretrix (19.50 g) 〉 R. philippinarum (18.28 g) 〉 S. constrzct (13.37 g) 〉 S.fuscescens (3.75 g). The highest number of spawning was 136 000 and the highest hatching rate of fetilizated eggs was 94.34%, which occurred in the group fed on R.philippinarum. The minimum number of spawning was 98 900 in the group fed on S.fuscescens, and the lowest of the hatching rate was 81.11% found in the control group. The average size of newly hatching larvae was 2.43 mm (R.philippinarum group) 〉 2.39 nun (M. meretrix and S. constrzct groups) 〉2.34 mm (S.fuscescens group) 〉 2.30 mm (control group). During the period of spawning and protecting, O. vuglaris can take food, about 2%-5% of its own weight, in order to improve hatching rate of eggs and the size of newly hatching larvae. R. philippinarum is the ideal food.%分别采用文蛤(Meretrix meretrix)、菲律宾蛤仔(Ruditapes philippinarum)、缢蛏(Sinonovacula constrzcta)、许氏平鲌(Sebastodes fuscescens)投喂处于产卵、护卵期的真蛸(Octopus vulgaris)亲体,通过测量亲蛸摄食量、产卵量、受精卵孵化率以及初孵幼体大小,分析4种不同饵料对亲体和幼体的影响。结果表明:亲蛸摄食量以文蛤投喂组最高,每只亲蛸每天平均摄食19.50g;菲律宾蛤仔组次之,为18.28g;缢蛏组较少,为13.39g;许氏平鲇组亲体摄食量最少,为3.75g。亲蛸产卵量和受精卵孵化率以菲律宾蛤仔投喂组最高,平均产卵量为13.6万

  16. Effects of Bioturbation on Vertical Distribution of Sediment Particles by Two Macrobenthos Species%两种大型底栖动物生物扰动对沉积物颗粒垂直分布的影响

    Institute of Scientific and Technical Information of China (English)

    吕洪斌; 王恕桥; 刘国山; 张秀梅

    2016-01-01

    Macrobenthos affect the physical, chemical and biological properties of the sediment-water interface. This bioturbation plays an important role in the biogeochemical processes of marine and lacustrine environments. Research has shown that bioturbation intensity depends on natural macrobenthos behavior, but is influenced by ex-ternal factors such as temperature, salinity, dissolved oxygen, macrobenthos density and food supply.In this stud-y,we investigated the effect of population density of a Polychaeta,Cirratulus chrysoderma, and size of a Bivalvia, Ruditapes philippinarum, on the vertical distribution of sediment particles.The two macrobenthos species were in-vestigated using polyvinyl chloride (PVC) tubes(L28 cm, D10.5 cm) with 15 cm of sediment.Glass beads(0.4-0.5 mm) were placed on the surface of the sediment as the tracer before the organisms were placed in the appa-ratus.The experiment was conducted at a salinity of 30 g/kg, temperature of 20℃and each treatment was run in triplicate.Treatment groups included three densities of C.chrysoderma (255, 510, 1 020 ind/m2),three sizes of R.philippinarum[large: (32.64 ±0.08) mm, (7.34 ±0.45) g;medium: (25.30 ±0.11) mm, (3.54 ± 0.19) g;small:(20.34 ±0.06) mm, (1.63 ±0.13) g)] and a control.The vertical distribution of tracers and macrobenthos for each treatment was determined on day 7 and day 20 of the experiment.The two macrobenthos spe-cies displayed significantly different bioturbation intensities, primarily because they belong to different bioturbation functional groups.The quantity and depth of tracer beads distributed in the sediments changed with C chrysoderma density, R philippinarum size and bioturbation time.The transport rate of tracer beads increased with density of C chrysoderma on day 7, but was negatively correlated on day 20.The transport rate of tracer beads decreased with size of R philippinarum at both sampling time.The maximum depth and number of tracer particles transported in the sediment

  17. Correlation between POPs in sediment and edible bivalve in the lagoon of Venice and estimation of the daily intake

    Energy Technology Data Exchange (ETDEWEB)

    Raccanelli, S.; Favotto, M. [Consorzio I.N.C.A., Venezia (Italy); Pastres, R. [Univ. of Venice (Italy); Vio, P. [Servizio Igiene Alimenti e Nutrizione, Regione Veneto (Italy)

    2004-09-15

    The lagoon of Venice, which is located in the Northern Adriatic Sea, is the largest Italian Lagoon, covering an area of about 550 km2. Its average depth is about 0.7 m, but its morphology is characterized by the presence of large shallow areas and by a network of deeper channels. As can be seen in Fig. 1, three narrow inlets connect the lagoon to the Adriatic Sea. The lagoon is conventionally partitioned into three sub-basins, which are separated by two watershed, along which the tidal velocity are low. In the last century the area of Porto Marghera, opposite the city of Venice, was converted into one of largest industrial area in Europe. As a result of the industrial activities, dioxin and dioxin-like compounds, as well as other classes of pollutants, were released into the environment. The lagoon sediment represented the main sink for this contaminants: in fact, concentrations higher than 2500 ng(I-TE)/kg were found in the sediment in the channels of the industrial area. At present, Tapes philippinarum is the target of an intensive fishing activity, which severely damages the lagoon sediment and the benthic community. Even though fishing is not allowed nearby the Industrial area, illegal catches of contaminated clams are still being commercialized. As a consequence, the risk for health of regular consumer of this bivalve should be estimated. In order to assess the risk and to reassure the consumers, In the year 2002, the main local fishermen association, CoVeAlLa, has set up a monitoring program of PCDD/F, PCB dioxinlike and HCB both in the sediment and in the flesh of the edible bivalve Tapes philippinarum. In this paper, we present and discuss the results which were obtained in the year 2003.

  18. Evaluation of the threat of marine CO{sub 2} leakage-associated acidification on the toxicity of sediment metals to juvenile bivalves

    Energy Technology Data Exchange (ETDEWEB)

    Basallote, M. Dolores, E-mail: dolores.basallote@uca.es [Cátedra UNESCO/UNITWIN WiCop, Departamento de Química-Física, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Polígono Río San Pedro s/n, 11510 Puerto Real, Cádiz (Spain); Rodríguez-Romero, Araceli [Departamento de Ecología y Gestión Costera, Instituto de Ciencias Marinas de Andalucía (CSIC), Campus Río San Pedro, 11510 Puerto Real, Cádiz (Spain); De Orte, Manoela R.; Del Valls, T. Ángel; Riba, Inmaculada [Cátedra UNESCO/UNITWIN WiCop, Departamento de Química-Física, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Polígono Río San Pedro s/n, 11510 Puerto Real, Cádiz (Spain)

    2015-09-15

    Highlights: • Short-term tests using juveniles of bivalves to study the effects of CO{sub 2} dissolved. • CO{sub 2} causes effects if the threshold concentration of the organism is overlapped. • Flows of escaped CO{sub 2} would affect the geochemical composition of sediment–seawater. • CO{sub 2}-induced acidification would affect differently to marine sediment toxicity. - Abstract: The effects of the acidification associated with CO{sub 2} leakage from sub-seabed geological storage was studied by the evaluation of the short-term effects of CO{sub 2}-induced acidification on juveniles of the bivalve Ruditapes philippinarum. Laboratory scale experiments were performed using a CO{sub 2}-bubbling system designed to conduct ecotoxicological assays. The organisms were exposed for 10 days to elutriates of sediments collected in different littoral areas that were subjected to various pH treatments (pH 7.1, 6.6, 6.1). The acute pH-associated effects on the bivalves were observed, and the dissolved metals in the elutriates were measured. The median toxic effect pH was calculated, which ranged from 6.33 to 6.45. The amount of dissolved Zn in the sediment elutriates increased in parallel with the pH reductions and was correlated with the proton concentrations. The pH, the pCO{sub 2} and the dissolved metal concentrations (Zn and Fe) were linked with the mortality of the exposed bivalves.

  19. Accumulation of heavy metals in bivalves shells of Jiaozhou Bay%胶州湾双壳类壳体中重金属元素的累积

    Institute of Scientific and Technical Information of China (English)

    刘升发; 范德江; 张爱滨; 颜文涛

    2008-01-01

    从胶州湾沿岸的7个取样点采集黄渤海近海常见的菲律宾蛤仔(Ruditapes philippinarum)、褶牡蛎(Oystrea denselamellosa)和紫贻贝(Mytilus galloprovincialis)三种双壳类软体动物,利用电感耦合等离子体质谱法(ICP-MS)对壳体中的重金属元素进行了测定以及数理统计,结果表明:双壳类壳体中Cr、Cu、Zn、Hg、Pb和Cd的平均含量分别为(269.33,1115.37,4845.81,6.89,19.47和366.06)×19-9,含量顺序Zn> Cu > Cd>Cr>Pb>Hg,与水体中的重金属含量顺序基本一致;三类双壳类壳体中重金属含量存在明显的种间差异性,多数重金属在菲律宾蛤仔壳体中含量高,而在褶牡蛎、紫贻贝壳体中含量较低;三类双壳类壳体对重金属具有相似的富集趋势,对Zn和Cu累积明显,富集系数达102数量级,其次为Pb,富集系数介于10~20之间,Cd的富集系数最低,小于10.

  20. MOLECULAR PHYLOGENY OF TAPETINAE (MOLLUSCA, BIVALVIA) BASED ON MTDNA SEQUENCE%缀锦蛤亚科(Tapetinae)贝类线粒体DNA序列的系统学分析

    Institute of Scientific and Technical Information of China (English)

    潘鹤婷; 袁媛; 吴琪; 张素萍; 潘宝平

    2008-01-01

    采用线粒体16S rRNA和COI序列扩增和测序方法,对隶属于缀锦蛤亚科5属7种动物进行了系统学分析.经Clustal x多重比对和PAuP 4.10 软件分析,得到种间序列的遗传距离并构建了邻接(NJ)系统树.实验数据显示,缀锦蛤亚科为遗传连续的同源类群,其中的浅蛤属(Gomphina)、缀锦蛤属(Tapes)和蛤仔属(Ruditapes)亲缘关系较近,结果与Fischer-Piette等(1971)的缀锦蛤亚科的分类方案基本一致.另外,菲律宾蛤仔R.philippinarum 和杂色蛤仔 R.variegata是蛤仔属在印度洋和太平洋海区的一个组群,尽管两种贝类有明显的重叠分布区和相近的贝壳形态,但二者间的16S rRNA 和COI序列遗传距离均达到了物种间差别.结果支持庄启谦(2001)有关菲律宾蛤仔与杂色蛤仔的形态分类及分布区划分的观点.

  1. Heavy metal concentrations in edible bivalves and gastropods available in major markets of the Pearl River Delta

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Molluscs are able to accumulate heavy metals and impose healthhazard to consumers. The main objective of the present study is to investigate the heavy metal concentrations in edible bivalves and gastropods available in major markets of the Pearl River Delta. Fourteen species of edible molluscs were purchased from six markets in Hong Kong and Guangdong Province. The fresh of these biota were tested for their cadmium (Cd), copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), chromium (Cr), antimony (Sb) and tin (Sn)concentrations (based on wet weight). The results indicated that amongst the 14 edible molluscs, only Cd, Pb, Ni, Cr, Sb and Sn concentrations in three species(Ruditapes philippinarum, Perna viridis and Hemifusus tuba) were within the local regulatory limits. Over 60% of bivalve species exceeded maximum permitted levels of Cd (2 μg/g) and Cr (1 μg/g), while over 40% of gastropod species exceeded the maximum levels of Sb (1 μg/g) and Cr(1 μg/g). Most of the samples collected from Hong Kong had significantly higher contents of Pb and Sb, but similar levels of Cd, Cu and Zn when compared with samples collected across the border (p<0.5; p<0.01; p<0.001 respectively). In general, the molluscs purchased in Guangdong markets had higher metal contents than those purchased from the Hong Kong markets. When compared with the Provisional Tolerable Weekly Intake or Maximum Acceptable Daily Load recommended by FAO/WHO Expert Committee on Food Additives, Cd levels of five species (Anadara ferruginea, Pinna pectinata, Chlamys nobilis, Babylonia lutosa and Hemifusus terntanus) and Cr levels of seven species (Anadara ferruginea, Paphia undulata, Pinna pectinata, Babylonia lutosa, Hemifusus terntanus, Cymbium melo and Cipangopaludina chinensis) were higher than both the human daily acceptable limits (for Cd and Cr respectively) and the local regulatory levels (for Cd and Cr respectively).

  2. Doubly uniparental inheritance of mitochondria as a model system for studying germ line formation.

    Directory of Open Access Journals (Sweden)

    Liliana Milani

    Full Text Available BACKGROUND: Doubly Uniparental Inheritance (DUI of mitochondria occurs when both mothers and fathers are capable of transmitting mitochondria to their offspring, in contrast to the typical Strictly Maternal Inheritance (SMI. DUI was found in some bivalve molluscs, in which two mitochondrial genomes are inherited, one through eggs, the other through sperm. During male embryo development, spermatozoon mitochondria aggregate in proximity of the first cleavage furrow and end up in the primordial germ cells, while they are dispersed in female embryos. METHODOLOGY/PRINCIPAL FINDINGS: We used MitoTracker, microtubule staining and transmission electron microscopy to examine the mechanisms of this unusual distribution of sperm mitochondria in the DUI species Ruditapes philippinarum. Our results suggest that in male embryos the midbody deriving from the mitotic spindle of the first division concurs in positioning the aggregate of sperm mitochondria. Furthermore, an immunocytochemical analysis showed that the germ line determinant Vasa segregates close to the first cleavage furrow. CONCLUSIONS/SIGNIFICANCE: In DUI male embryos, spermatozoon mitochondria aggregate in a stable area on the animal-vegetal axis: in organisms with spiral segmentation this zone is not involved in cleavage, so the aggregation is maintained. Moreover, sperm mitochondria reach the same embryonic area in which also germ plasm is transferred. In 2-blastomere embryos, the segregation of sperm mitochondria in the same region with Vasa suggests their contribution in male germ line formation. In DUI male embryos, M-type mitochondria must be recognized by egg factors to be actively transferred in the germ line, where they become dominant replacing the Balbiani body mitochondria. The typical features of germ line assembly point to a common biological mechanism shared by DUI and SMI organisms. Although the molecular dynamics of the segregation of sperm mitochondria in DUI species are unknown

  3. Seasonal distribution of bromophenols in selected Hong Kong seafood.

    Science.gov (United States)

    Chung, Hau Yin; Joyce Ma, Wing Chi; Kim, Joo-Shin

    2003-11-01

    Selected seafood including rabbitfish (Siganus canaliculatus), brown-spotted grouper (Epinephelus areolatus), clam (Tapes philippinarum), oyster (Ostrea rivularis), shrimp (Penaeus japonicus), and crab (Charybdis feriatus), commonly found in the Hong Kong wet market, was monitored for their distribution and seasonal variations of their bromophenol contents. Specifically, 2-bromophenol (1). 4-bromophenol (2). 2,4-dibromophenol (3). 2,6-dibromophenol (4). and 2,4,6-tribromophenol (5). were monitored due to their flavor impact to seafood. All samples of marine origin contained bromophenols throughout a year. Crab had the highest concentration of total bromophenol content throughout the season. Concentrations of compounds 1, 4, and 5 in the local seafood were generally higher than that found in the literature values to provide characteristic flavor, but lower than that required to cause off-flavor. Variations of the flavor impact of bromophenols in seafood during a season could be better shown by their flavor values. Distribution and seasonal variations of bromophenol content in seafood coincided well with the seasonal growth cycle of the bromophenol synthesizing seaweeds, e.g. brown algae, in the region suggesting the abundant source of bromophenols in the environment might have a high impact on the quantity of bromophenols found in seafood.

  4. Universal Virus Adsorption on Inert Particles Utilizing the Coated Latex Adsorption Method (CLAM)

    Science.gov (United States)

    1975-06-30

    autoimmune processes such as autoimmune hemolytic anemia or erythro- blastosis fetalis. Cell mediated immunity includes graft rejection, delayed hyper...activated antigen-primed cellst A computer simulation. J. Immunol. 107:115-122. 18. Conrad, R. E. and J. S. Ingraham. 1974. Rate of hemolytic anti- body...infected; and the rate of removal of infected virus. This information is of great value in the diagnosis of viral infection under natural conditions

  5. KBWOT 2012: the use of an acoustic technique in mapping beds of razor clams (Ensis sp.)

    NARCIS (Netherlands)

    Troost, K.; Asch, van M.; Baeye, M.; Brummelhuis, E.B.M.; Davaasuren, N.; Ende, van den D.; Lancker, van V.

    2013-01-01

    For the survey of shellfish in the Dutch coastal zone (WOT Ensis), a fixed stratified sampling grid is used. Stratification is based on expectation of occurrence, for which previously observations by Spisula fishermen were used. Spisula subtruncata has largely disappeared and was replaced by Ensis s

  6. Clam Shell Dredging in Lakes Pontchartrain and Maurepas, Louisiana. Volume 3. Responses to Public Comments.

    Science.gov (United States)

    1987-11-01

    partially offset by increased employment in the production of alternative materials elsewhere. The net national employment effects of making such a market ...adjacent to the lakes or the shallow nearshore waters adjacent to the lakes. Impacts to duck hunting and birdwatching would be immeasurably small. 75...i.e., more efficient, product. Thus, any substitute good by definition could only partially offset the adverse impact of denying market access to the

  7. 76 FR 65180 - Proposed Information Collection; Comment Request; Application to Shuck Surf Clams/Ocean Quahogs...

    Science.gov (United States)

    2011-10-20

    ... Exclusive Economic Zone (EEZ) of the Northeastern United States through the Atlantic Surfclam and Ocean...). Affected Public: Business or other for-profit organizations. Estimated Number of Respondents: 205... proposed collection of information is necessary for the proper performance of the functions of the...

  8. Sulfide oxidizing activity as a survival strategy in mangrove clam Polymesoda erosa (Solander, 1786)

    Digital Repository Service at National Institute of Oceanography (India)

    Clemente, S.; Ingole, B.S.; Sumati, M.; Goltekar, R.

    at Chapora (2.5x10 sup(9) to 4.5x10 sup(9)) and lower values were at Siolim (1x10 sup(9) to 2x10 sup(9)). The total number of bacteria per gram of fresh tissue of P. erosa was highest (3.8x10 sup(9)) in Chorao station in the size class of 7.0-7.9 cm whereas...

  9. Of "Chicharrones" and Clam Chowder: Gender and Consumption in Jorge Ulica's Cronicas Diabolicas

    Science.gov (United States)

    Barrera, Magdalena

    2009-01-01

    This essay examines the working-class Mexican experience as represented in Jorge Ulica's "Cronicas Diabolicas," which he published between 1916 and 1926. What unites the wide-ranging subject matter of the chronicles is the author's resolute interest in maintaining his working-class compatriots' cultural and ideological ties to Mexico.…

  10. Sandeels and clams (Spisula sp.) in the wind turbine park at Horns Reef. Preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Henrik; Sand Kristensen, P.; Hoffmann, E.

    2003-04-15

    Sandeels were found in the sediment at all of the sample locations in the area of the wind turbine park and in the control area. The mean density of sandeels in the sediment was 0.0102 m{sup -2} (10,200 km{sup -2}) in the control area and 0.0096 m{sup -2} (9,600 km{sup -2}) in the impact area. The most abundant species of sandeel in both the impact and the control area was H. lanceolatus followed by A. marinus and A. tobianus. No G. semisquamatus was caught during the surveys. The construction of the wind turbine park is not supposed to effect the sandeel population in the Horns Reef area because the impact area seems to constitute a small fraction of a larger area with sandeel habitat. However, within the area of the wind turbine park sandeel abundance might be affected if the surface sediment changes due to the construction of the wind turbine park or if the abundance of sandeel predators increases in the impact area after the wind turbine park has been build (the so called artificial reef effect). To investigate if these effects will occur the field programmethat was carried out in February/march 2002 (the subject of this report) will have to be repeated after the wind turbine park has been constructed. (au)

  11. CD63 Promotes Hemocyte-Mediated Phagocytosis in the Clam, Paphia undulata

    Directory of Open Access Journals (Sweden)

    Mingjia Yu

    2016-01-01

    Full Text Available As one of the surface membrane proteins of tetraspanin family, CD63 plays a crucial role in cellular trafficking and endocytosis, which also is associated with activation of a wide variety of immune cells. Here, the homolog of CD63 was characterized from one marine mollusk, Paphia undulata, which is designated as Pu-CD63. The complete cDNA of Pu-CD63 is 1,738 bp in length with an open reading frame (ORF of 849 bp, encoding a 282 amino acid protein with four putative hydrophobic transmembrane helixes. Bioinformatic analysis revealed that Pu-CD63 contains one putative YXXØ consensus motif of “110-YVII-113” and one N-glycosylation site “155-NGT-157” within the large extracellular loop (LEL region, supporting its conserved function in plasma membrane and endosomal/lysosomal trafficking. Moreover, temporal expression profile analysis demonstrates a drastic induction in the expression of CD63 in hemocytes after pathogenic challenge with either V. parahaemolyticus or V. alginolyticus. By performing dsRNA-mediate RNAi knockdowns of CD63, a dramatic reduction in hemocytes phagocytic activity to pathogenic Vibrio is recorded by flow cytometry, revealing the definite role of Pu-CD63 in promoting hemocyte-mediated phagocytosis. Therefore, our work has greatly enhanced our understanding about primitive character of innate immunity in marine mollusk.

  12. Uranium in the Near-shore Aquatic Food Chain: Studies on Periphyton and Asian Clams

    Energy Technology Data Exchange (ETDEWEB)

    Bunn, Amoret L.; Miley, Terri B.; Eslinger, Paul W.; Brandt, Charles A.; Napier, Bruce A.

    2007-12-31

    The benthic aquatic organisms in the near-shore environment of the Columbia River are the first biological receptors that can be exposed to groundwater contaminants coming from the U.S. Department of Energy's Hanford Site. The primary contaminant of concern in the former nuclear fuels processing area at the Site, known as the 300 Area, is uranium. Currently, there are no national clean up criteria for uranium and ecological receptors. This report summarizes efforts to characterize biological uptake of uranium in the food chain of the benthic aquatic organisms and provide information to be used in future assessments of uranium and the ecosystem.

  13. Biochemical changes during larval development in the short neck clam, Paphia malabarica Chemnitz

    Digital Repository Service at National Institute of Oceanography (India)

    Gireesh, R.; Biju, A.; Muthiah, P.

    of embryogenesis, 2.6% of the protein, 11.8% of the lipid and 3.2% of carbohydrate mass had been lost, providing 20.5%,75.4% and 4.1% of the total energy expenditure of 0.2147 mJ embryo sup(-1). During 48h of metamorphosis, lipid was utilized first, followed by a...

  14. Of "Chicharrones" and Clam Chowder: Gender and Consumption in Jorge Ulica's Cronicas Diabolicas

    Science.gov (United States)

    Barrera, Magdalena

    2009-01-01

    This essay examines the working-class Mexican experience as represented in Jorge Ulica's "Cronicas Diabolicas," which he published between 1916 and 1926. What unites the wide-ranging subject matter of the chronicles is the author's resolute interest in maintaining his working-class compatriots' cultural and ideological ties to Mexico. Ulica…

  15. 基于Tenax脱附动力学的沉积物中菊酯类农药生物有效性研究%Research on Bioavailability of Pyrethroids in Sediments Based on Tenax Desorption Kinetics

    Institute of Scientific and Technical Information of China (English)

    李娟英; 陈美娜; 李振华; 胡谦; 郑易

    2015-01-01

    Pyrethroids have been widely used in agriculture, forestry and fisheries as pesticide, and frequently detected in sediment because of their high hydrophobicity and lipotrophy. It is, therefore, of great significance to the assessment of en⁃vironmental quality and risk to study bioavailability of these compounds in sediments. Tenax desorption kinetics of four py⁃rethroids (cyhalothrin, bifenthrin, permethrin and fenpropathrin) were analyzed to evaluate bioavailability of the pyre⁃throids in sediments of the tidal zone in the Yangshan Port, meanwhile results of the Tenax extraction were compared with those of the experiment on bioaccumulation of pyrethroids in Ruditapes philippinarum. Results show that the fraction of readily desorbable pyrethroids ( Frap ) accounted for over 50% in the surface sediments low in organic carbon ( OC ) content, and the desorption rate of the fractions of readily, slowly and very slowly desorbable pyrethroids varied in magni⁃tude order, being 10-1 , 10-2 and 10-5-10-3 , respectively. Compared with Frap , single time⁃point Tenax extraction can be used to evaluate bioavailability of pyrethroid pesticides in sediments, rapidly, economically and effectively. Correlation a⁃nalysis shows that 24 h Tenax ( Cs,24 h ) extraction is more suitable to application to the prediction of pyrethroid accumula⁃tion concentrations in Ruditapes philippinarum ( Cb ) ( lg Cb=4�03 lg Cs,24 h-17�02,R2=0�88,P<0�05) . The findings of this study may not only provide reliable scientific basis for simple rapid evaluation of bioavailability of pyrethroids in sedi⁃ments and assessment of environmental quality and risk of marine sediments, but also be used to predict bioaccumulation of permethrin pesticides in bivalve oobenthos, and furthermore, as a simpler and easier method for environmental risk as⁃sessment of aquaculture sediments and food risk assessment of relevant aquatic products.%菊酯类农药已被广泛应用于农业、林业和

  16. Selective Feeding on Five Species of Bivalves and Feeding Rhythm of Asterias amurensis%多棘海盘车(Asterias amurensis)对5种双壳贝类的摄食选择性及摄食节律

    Institute of Scientific and Technical Information of China (English)

    代克涛; 李娇; 关长涛; 张媛; 赵学伟

    2015-01-01

    研究了多棘海盘车(Asterias amurensis)对虾夷扇贝(Patinopecten yessoensis)、栉孔扇贝(Chlamys farreri)、褶牡蛎(Ostrea plicatula)、贻贝(Mytilus galloprovincialis)、菲律宾蛤仔(Ruditapes philippinarum)5种双壳贝类的摄食选择性和对栉孔扇贝的摄食节律。结果显示,在有或无日本蟳、刺参等干扰饵料的条件下,多棘海盘车对于5种双壳贝类均可摄食,且表现出明显的摄食选择性。其中,多棘海盘车对菲律宾蛤仔的摄食选择性均显著高于其他4种贝类(P<0.05),分别为5.7、5.0、5.7、5.3、6.0只/d,干扰饵料的加入并没有对多棘海盘车的摄食选择性造成显著影响。同时,采用定时投喂饵料的方式,每隔4 h投喂一次栉孔扇贝,多棘海盘车表现出显著地昼夜摄食节律。其18:00–翌日06:00的摄食量显著高于06:00–18:00的摄食量(P<0.05),分别为60%和40%,多棘海盘车的摄食高峰出现在18:00–22:00,摄食频率达到58%,显著高于其他时段(P<0.05)。%Asterias amurensis is one of the primary predators of bivalves that often cause massive death of cultured bivalves. Better understanding of the feeding ecophysiology of A. amurensis is the key for developing effective control strategies. In this study, we recorded the selective feeding and feeding rhythm of A. amurensis on five species of bivalves including Patinopecten yessoensis, Chlamys farreri, Ostrea plicatula, Mytilus galloprovincialis and Ruditapes philippinarum, and thus identified the characteristics of feeding of A. amurensis. The experimental animals were collected from the sea area of Zhangzi Island and then transported to our seaside laboratory at low temperature. The A. amurensis was acclimated to laboratory conditions for 10 d before the experiment. The experiment was conducted between October 22 and November 12, 2013, at the water temperature of 13−15℃, and at the salinity of 30−31, and at the dissolved

  17. Separation and Purification of Natural Taurine Using Ceramic and Ultrafiltration Membrane Technology%利用陶瓷膜和超滤膜组合技术分离纯化天然牛磺酸

    Institute of Scientific and Technical Information of China (English)

    章骞; 崔璨; 邱娟; 雷桂英; 张凌晶; 曹敏杰

    2016-01-01

    运用陶瓷膜和超滤膜组合技术对杂色蛤(Ruditapes philippinarum)蒸煮汤汁中的牛磺酸进行分离纯化,再经浓缩、醇沉、结晶、重结晶等步骤获得高纯度天然牛磺酸.利用高效液相色谱法测定牛磺酸纯度,并对其进行扫描电镜分析和急性毒性试验.结果显示,截留孔径为0.2 μm的陶瓷膜在平均压力0.24 MPa、平均温度30 ℃、自然pH值下运行120 min后,平均膜通量为32.86L/(m2 ·h),牛磺酸损失率为4.99%;截留分子质量为100 ku的超滤膜在平均压力0.84 MPa、平均温度30℃、自然pH值下运行210 min后,平均膜通量为19.97 L/(m2·h),牛磺酸损失率为5.51%.再经浓缩、醇沉、结晶处理后,可从1OL杂色蛤蒸煮汤汁中获得纯度为84%的天然牛磺酸18.87 g,重结晶后得纯度为98.7%的天然牛磺酸.扫描电子显微镜观测结果显示,天然牛磺酸晶体形态为长针状.急性毒性试验结果显示,天然牛磺酸的LD50> 10 g/kg,属于实际无毒或无毒物质.

  18. 福建省东山湾生态环境中多氯联苯的残留特征%Residual characteristics of PCBs in ecological environment of Dongshan Bay in Fujian Province

    Institute of Scientific and Technical Information of China (English)

    余颖; 姜琳琳; 钟硕良

    2014-01-01

    对福建省东山湾海域的水质、沉积物和养殖贝类中的多氯联苯(polychlorinated biphenyls,PCBs)残留进行气相色谱法检测,并对其在水域环境及贝类中的残留水平、生态风险及食用安全进行了探讨.结果表明:1)海水中PCBs质量浓度底层高于表层;夏季(8月)高于春季(5月).总体上,东山湾海水中PCBs质量浓度的平面分布从湾内到湾外呈递减趋势.底层海水中PCBs与悬浮物质量浓度之间具有极显著的相关性.2)表层沉积物中PCBs残留的平面分布呈近岸高、湾中部和湾外低的格局;PCBs与总有机碳(TOC)质量分数之间呈极显著正相关.PCBs残留量产生的生物有害效应的风险低.3)养殖贝类体中PCBs的残留量种间差异明显,对PCBs富集能力的大小,僧帽牡蛎(Saccostrea cucullata)、缢蛏(Sinonovacula constricta)和波纹巴非蛤(Paphia undulate)最高,泥蚶(Tegillarca granosa)和华贵栉孔扇贝(Chlamys nobilis)次之,菲律宾蛤仔(Ruditapes philippinarum)和杂色鲍(Haliotis diversicolor)最低.养殖贝类致癌风险指数在可接受风险范围内,贝类体中的PCBs残留水平居福建省沿海养殖贝类中等水平.

  19. Prevalences of pathogenic and nonpathogenic Vibrio parahaemolyticus in mollusks from the Spanish Mediterranean Coast

    Directory of Open Access Journals (Sweden)

    Carmen eLopez-Joven

    2015-07-01

    Full Text Available Vibrio parahaemolyticus is a well-recognized pathogen of humans. To better understand the ecology of the human-pathogenic variants of this bacterium in the environment, a study on the prevalence in bivalves of pathogenic variants (tlh + and tdh+ and/or trh+ versus a nonpathogenic one (only tlh+ as species marker for V. parahaemolyticus, was performed in two bays in Catalonia, Spain. Environmental factors that might affect dynamics of both variants of V. parahaemolyticus were taken into account. The results showed that the global prevalence of total V. parahaemolyticus found in both bays was 14.2% (207/1459. It was, however, significantly dependent on sampling point, campaign (year and bivalve species. Pathogenic variants of V. parahaemolyticus (tdh+ and/or trh+ were detected in 3.8% of the samples (56/1459, meaning that the proportion of bivalves who contained tlh gene were contaminated by pathogenic V. parahaemolyticus strains is 27.1% (56/207. Moreover, the presence of pathogenic V. parahaemolyticus (trh+ was significantly correlated with water salinity, thus the probability of finding pathogenic V. parahaemolyticus decreased 1.45 times with every salinity unit (ppt increased. Additionally, data showed that V. parahaemolyticus could establish close associations with Ruditapes spp. (P-value < 0.001, which could enhance the transmission of illness to human by pathogenic variants, when clams were eaten raw or slightly cooked.This study provides information on the abundance, ecology and characteristics of total and human-pathogenic V. parahaemolyticus variants associated with bivalves cultured in the Spanish Mediterranean Coast.

  20. Prevalences of pathogenic and non-pathogenic Vibrio parahaemolyticus in mollusks from the Spanish Mediterranean Coast.

    Science.gov (United States)

    Lopez-Joven, Carmen; de Blas, Ignacio; Furones, M Dolores; Roque, Ana

    2015-01-01

    Vibrio parahaemolyticus is a well-recognized pathogen of humans. To better understand the ecology of the human-pathogenic variants of this bacterium in the environment, a study on the prevalence in bivalves of pathogenic variants (tlh+ and tdh+ and/or trh+) versus a non-pathogenic one (only tlh+ as species marker for V. parahaemolyticus), was performed in two bays in Catalonia, Spain. Environmental factors that might affect dynamics of both variants of V. parahaemolyticus were taken into account. The results showed that the global prevalence of total V. parahaemolyticus found in both bays was 14.2% (207/1459). It was, however, significantly dependent on sampling point, campaign (year) and bivalve species. Pathogenic variants of V. parahaemolyticus (tdh+ and/or trh+) were detected in 3.8% of the samples (56/1459), meaning that the proportion of bivalves who contained tlh gene were contaminated by pathogenic V. parahaemolyticus strains is 27.1% (56/207). Moreover, the presence of pathogenic V. parahaemolyticus (trh+) was significantly correlated with water salinity, thus the probability of finding pathogenic V. parahaemolyticus decreased 1.45 times with every salinity unit (ppt) increased. Additionally, data showed that V. parahaemolyticus could establish close associations with Ruditapes spp. (P-value < 0.001), which could enhance the transmission of illness to human by pathogenic variants, when clams were eaten raw or slightly cooked. This study provides information on the abundance, ecology and characteristics of total and human-pathogenic V. parahaemolyticus variants associated with bivalves cultured in the Spanish Mediterranean Coast.

  1. Liquid Chromatography with a Fluorimetric Detection Method for Analysis of Paralytic Shellfish Toxins and Tetrodotoxin Based on a Porous Graphitic Carbon Column

    Directory of Open Access Journals (Sweden)

    Veronica Rey

    2016-06-01

    Full Text Available Paralytic shellfish toxins (PST traditionally have been analyzed by liquid chromatography with either pre- or post-column derivatization and always with a silica-based stationary phase. This technique resulted in different methods that need more than one run to analyze the toxins. Furthermore, tetrodotoxin (TTX was recently found in bivalves of northward locations in Europe due to climate change, so it is important to analyze it along with PST because their signs of toxicity are similar in the bioassay. The methods described here detail a new approach to eliminate different runs, by using a new porous graphitic carbon stationary phase. Firstly we describe the separation of 13 PST that belong to different groups, taking into account the side-chains of substituents, in one single run of less than 30 min with good reproducibility. The method was assayed in four shellfish matrices: mussel (Mytillus galloprovincialis, clam (Pecten maximus, scallop (Ruditapes decussatus and oyster (Ostrea edulis. The results for all of the parameters studied are provided, and the detection limits for the majority of toxins were improved with regard to previous liquid chromatography methods: the lowest values were those for decarbamoyl-gonyautoxin 2 (dcGTX2 and gonyautoxin 2 (GTX2 in mussel (0.0001 mg saxitoxin (STX·diHCl kg−1 for each toxin, decarbamoyl-saxitoxin (dcSTX in clam (0.0003 mg STX·diHCl kg−1, N-sulfocarbamoyl-gonyautoxins 2 and 3 (C1 and C2 in scallop (0.0001 mg STX·diHCl kg−1 for each toxin and dcSTX (0.0003 mg STX·diHCl kg−1 in oyster; gonyautoxin 2 (GTX2 showed the highest limit of detection in oyster (0.0366 mg STX·diHCl kg−1. Secondly, we propose a modification of the method for the simultaneous analysis of PST and TTX, with some minor changes in the solvent gradient, although the detection limit for TTX does not allow its use nowadays for regulatory purposes.

  2. Liquid Chromatography with a Fluorimetric Detection Method for Analysis of Paralytic Shellfish Toxins and Tetrodotoxin Based on a Porous Graphitic Carbon Column.

    Science.gov (United States)

    Rey, Veronica; Botana, Ana M; Alvarez, Mercedes; Antelo, Alvaro; Botana, Luis M

    2016-06-28

    Paralytic shellfish toxins (PST) traditionally have been analyzed by liquid chromatography with either pre- or post-column derivatization and always with a silica-based stationary phase. This technique resulted in different methods that need more than one run to analyze the toxins. Furthermore, tetrodotoxin (TTX) was recently found in bivalves of northward locations in Europe due to climate change, so it is important to analyze it along with PST because their signs of toxicity are similar in the bioassay. The methods described here detail a new approach to eliminate different runs, by using a new porous graphitic carbon stationary phase. Firstly we describe the separation of 13 PST that belong to different groups, taking into account the side-chains of substituents, in one single run of less than 30 min with good reproducibility. The method was assayed in four shellfish matrices: mussel (Mytillus galloprovincialis), clam (Pecten maximus), scallop (Ruditapes decussatus) and oyster (Ostrea edulis). The results for all of the parameters studied are provided, and the detection limits for the majority of toxins were improved with regard to previous liquid chromatography methods: the lowest values were those for decarbamoyl-gonyautoxin 2 (dcGTX2) and gonyautoxin 2 (GTX2) in mussel (0.0001 mg saxitoxin (STX)·diHCl kg(-1) for each toxin), decarbamoyl-saxitoxin (dcSTX) in clam (0.0003 mg STX·diHCl kg(-1)), N-sulfocarbamoyl-gonyautoxins 2 and 3 (C1 and C2) in scallop (0.0001 mg STX·diHCl kg(-1) for each toxin) and dcSTX (0.0003 mg STX·diHCl kg(-1) ) in oyster; gonyautoxin 2 (GTX2) showed the highest limit of detection in oyster (0.0366 mg STX·diHCl kg(-1)). Secondly, we propose a modification of the method for the simultaneous analysis of PST and TTX, with some minor changes in the solvent gradient, although the detection limit for TTX does not allow its use nowadays for regulatory purposes.

  3. Installation Summaries From the FY 2001 Survey of Threatened and Endangered Species on Army Lands

    Science.gov (United States)

    2002-08-01

    Dromedary pearlymussel Contiguous E Clam No Epioblasma florentina walkeri Tan riffleshell Contiguous E Clam No Lampsilis abrupta Pink mucket...Barracks Military Reservation Onsite No Dromus dromas Dromedary pearlymussel E Clam FORSCOM 4 Fort Campbell Contiguous No Drymarchon corais

  4. Laboratory experiment, the number of clams consumed by the fish of FLORIDA POMPANO in experimental tanks feeding on coquina clams individually and in groups from 2013-11-26 to 2013-12-03 (NCEI Accession 0127553)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset includes the results from a laboratory experiment assessing whether juvenile Florida Pompano (Trachinotus carolinus) foraging success is greater when in...

  5. The Early Development of the Short-Necked Clam, Paphia undulata (Born 1778 (Mollusca, Pelecypoda: Veneridae in the Laboratory

    Directory of Open Access Journals (Sweden)

    Annabelle del Norte Campos

    2010-12-01

    Full Text Available The population of Paphia undulata in Negros Occidental waters continues to decline due to unregulated harvesting because of the increasing demand for this resource. One potential effort to mitigate this problem is reseeding or stock enhancement of the natural population. For these efforts to be effective however, successful laboratory rearing and breeding of this species is a prerequisite. Thus, this study was conducted to describe the embryonic and larval development of P. undulata to provide information on laboratory larval rearing. Broodstock were collected during the natural spawning peak from Hinigaran, Negros Occidental and were maintained in a static system with a mean salinity and temperature of 36 ppt. and 26.7 OC, respectively and were fed with Isochrysis galbana, Chaetoceros calcitrans, and Tetraselmis tetrahele. Fertilized eggs started to divide 30 minutes after fertilization. Ciliated swimming blastulas were observed after 1.5 hours with an average shell length (SL of 40 µm. These further developed into trocophore larvae (average SL 60µm after 7 hours and into D-veliger (average SL 80 µm after 12 hours. Fully developed D-larvae (average SL 90 µm were attained after 17 hours. Larvae with completely developed umbo were observed on day 9 with an average SL of 140 µm. On day 13, larvae (average SL 220 µm started to settle and metamorphose. Spontaneous spawning was observed during the peak of reproductive activities of P. undulata showing that collection of broodstock must be conducted during the peak of reproductive season to ensure successful spawning and production of viable gametes under laboratory conditions. Further experiments should be conducted to determine optimum conditions to improve survival rates of the larvae during settlement. The results corroborate other studies and help explain the derived information on the species' population and reproductive biology.

  6. Vanishing clams on an Iberian beach: local consequences and global implications of accelerating loss of shells to tourism.

    Science.gov (United States)

    Kowalewski, Michał; Domènech, Rosa; Martinell, Jordi

    2014-01-01

    Multi-decadal increase in shell removal by tourists, a process that may accelerate degradation of natural habitats, was quantified via two series of monthly surveys, conducted thirty years apart (1978-1981 and 2008-2010) in one small embayment on the Mediterranean coast of the Iberian Peninsula. Over the last three decades, the local tourist arrivals have increased almost three-fold (2.74), while the area has remained unaffected by urban encroachment and commercial fisheries. During the same time interval the abundance of mollusk shells along the shoreline decreased by a comparable factor (2.62) and was significantly and negatively correlated with tourist arrivals (r = -0.52). The strength of the correlation increased when data were restricted to months with high tourist arrivals (r = -0.72). In contrast, the maximum monthly wave energy (an indirect proxy for changes in rate of onshore shell transport) was not significantly correlated with shell abundance (r = 0.10). Similarly, rank dominance of common species, drilling predation intensity, and body size-frequency distribution patterns have all remained stable over recent decades. A four-fold increase in global tourist arrivals over the last 30 years may have induced a comparable worldwide acceleration in shell removal from marine shorelines, resulting in multiple, currently unquantifiable, habitat changes such as increased beach erosion, changes in calcium carbonate recycling, and declines in diversity and abundance of organisms, which are dependent on shell availability.

  7. The Pacific clam Nutricola tantilla (Bivalvia:Veneridae) has separate sexes and makes use of brood protection and sperm storage

    DEFF Research Database (Denmark)

    Lützen, Jørgen; Jespersen, Åse; Russell, Michael P.

    2015-01-01

    Et morfologisk studie af en NW Amerikansk blødbunds-musling Nutricola tantilla viste at den er særkønnet og ikke, som tidligere rapporteret, protandrisk hermafrodit. Vi baserer denne konklusion på at små hanner har højt specialiserede kirtelholdige spermiodukter, mens større hunner har simple ovi...

  8. Effect of variations in concentration of algae and silt on filtration and growth of the razor clam (Ensis directus, Conrad)

    NARCIS (Netherlands)

    Kamermans, P.; Dedert, M.

    2012-01-01

    As part of a collaboration between the research programme Knowledge for Primary Processes Silt of Rijkswaterstaat Waterdienst NWOB (department of Infrastructure and Environment, MinIenM, RWS) and the Monitoring programme Sand extraction RWS and the LaMER Foundation, RWS-WD NWOB requested further res

  9. Assimilation of terrigenous organic matter via bacterial biomass as a food source for a brackish clam, Corbicula japonica (Mollusca: Bivalva)

    Science.gov (United States)

    Yamanaka, Toshiro; Mizota, Chitoshi; Maki, Yonosuke; Matsumasa, Masatoshi

    2013-07-01

    Corbicula japonica collected from the Kitakami River estuary, northeastern Japan, showed lower δ34S values in soft-body parts (+1.7 to +11.0‰) than the ambient seawater sulfate sulfur (+21‰), and this value gradually decreased at successive sites up to 15.8 km upstream from the river mouth. Previous study using carbon and nitrogen isotopes suggests that the bivalve nonselectively assimilates particulate organic matter of marine and terrestrial origin by filter feeding. This pattern in δ34S values may indicate a considerable contribution of a food source derived from terrigenous organic matter, which has low δ34S values close to 0‰, and the bivalve has been reported to have cellulase and hemicellulase activities. Unique fatty acids (iso 17:0 and anteiso 17:0 acids), both characteristic of sulfate-reducing bacteria, were observed in the salt-free, soft-body parts of the bivalve. The concentration of monounsaturated fatty acids, possibly derived from bacteria, was also high. Trace amounts of a polyunsaturated fatty acid (20:5ω3) specific to dinoflagellates were detected. In Corbicula habitats, reductive sandy layers with ample sulfides that were sporadically intercalated into the oxidative sandy sediment were often observed. The stable isotopic signatures of sediment sulfides (acid-volatile sulfide) and associated pore-water sulfates were -8.9 to +8.6‰ and +22.4 to +26.3‰, respectively, indicating the existence of bacterial sulfate-reducing activity and thiobios biomass. These isotopic signatures of the sediment, with the fatty acid composition of the bivalve, confirm the importance of a food source derived from bacteria belonging to the thiobios in the substrate sediments via pedal feeding, rather than direct digestion of terrigenous organic matter, in this estuarine ecosystem.

  10. THE PHYLOGENETIC RELATIONSHIPS OF WHALE-FALL VESICOMYID CLAMS BASED ON MITOCHONDRIAL COI DNA SEQUENCES. (U915626)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  11. Distribution and growth of Vibrio parahaemolyticus in southern Chilean clams (Venus antiqua) and blue mussels (Mytilus chilensis).

    Science.gov (United States)

    Aranda, Carlos P; Yévenes, Marco; Rodriguez-Benito, Cristina; Godoy, Félix A; Ruiz, Magdalena; Cachicas, Viviana

    2015-01-01

    We evaluated the distribution and growth of Vibrio parahaemolyticus in the inland sea of southern Chile, where the world's largest foodborne gastroenteritis outbreak by the pandemic strain O3:K6 occurred in 2005. Intertidal samples of Mytilus chilensis and Venus antiqua were collected around port towns between 41°28'S and 43°07'S, during April to May 2011 and January to March 2012. We used most probable number real-time polymerase chain reaction (MPN-PCR) for enumeration of the tlh, tdh, and trh genes in freshly harvested bivalves and after a controlled postharvest temperature abuse. Pathogenic markers (tdh+ or trh+) were not detected. Total V. parahaemolyticus (tlh+) in freshly harvested samples reached up to 0.38 and 3.66 log MPN/g in 2011 and 2012, respectively, with values close to or above 3 log MPN/g only near Puerto Montt (41°28'S, 72°55'W). Enrichments by temperature abuse (>2 log MPN/g) occurred mainly in the same zone, regardless of the year, suggesting that both natural or anthropogenic exposure to high temperatures were more critical. Lower salinity and higher sea surface temperature in Reloncaví Sound and Reloncaví Estuary were consistent with our observations and allowed confirmation of the existence of a high-risk zone near Puerto Montt. Based on the results, a strategy focused on risk management inside this defined hazard zone is recommended.

  12. Bio-accumulation of some trace metals in the short-neck clam Paphia malabarica from Mandovi estuary, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    KrishnaKumari, L.; Kaisary, S.; Rodrigues, V.

    exhibit trends similar to one another with peaks in September and December-January in both the size groups. Cadmium accumulation was highest in the mantle and adductor muscle, Lead, in foot, Copper, in digestive gland and gonad, and Zn and Fe, in gills...

  13. Oxidation Behavior of α-alumina Scales on Fe-Al Diffusion Coating of China Activation Martensitic Steel(CLAM)

    Institute of Scientific and Technical Information of China (English)

    ZHAN; Qin; YANG; Hong-guang; ZHAO; Wei-wei; YUAN; Xiao-ming; ZHU; Xin-xin

    2013-01-01

    It is well known thatα-Al2O3 phase has stable,high permeation reduction factor(PRF)and good resistance performance in liquid LiPb,which is considered as the reference tritium permeation barriercoating in future fusion reactor.In order to study the formation mechanism of stableα-Al2O3 scales on fusion structure material,the oxidation behavior of Fe-Al diffusion coating on China Low Activation

  14. From the test tube to the cell: exploring the folding and aggregation of a beta-clam protein.

    Science.gov (United States)

    Ignatova, Zoya; Krishnan, Beena; Bombardier, Jeffrey P; Marcelino, Anna Marie C; Hong, Jiang; Gierasch, Lila M

    2007-01-01

    A crucial challenge in present biomedical research is the elucidation of how fundamental processes like protein folding and aggregation occur in the complex environment of the cell. Many new physico-chemical factors like crowding and confinement must be considered, and immense technical hurdles must be overcome in order to explore these processes in vivo. Understanding protein misfolding and aggregation diseases and developing therapeutic strategies to these diseases demand that we gain mechanistic insight into behaviors and misbehaviors of proteins as they fold in vivo. We have developed a fluorescence approach using FlAsH labeling to study the thermodynamics of folding of a model beta-rich protein, cellular retinoic acid binding protein (CRABP) in Escherichia coli cells. The labeling approach has also enabled us to follow aggregation of a modified version of CRABP and chimeras between CRABP and huntingtin exon 1 with its glutamine repeat tract. In this article, we review our recent results using FlAsH labeling to study in-vivo folding and present new observations that hint at fundamental differences between the thermodynamics and kinetics of protein folding in vivo and in vitro.

  15. Clam Shell Dredging in Lakes Pontchartrain and Maurepas, Louisiana. Volume 1. Final Environmental Impact Statement and Appendixes

    Science.gov (United States)

    1987-11-01

    Mr.Gerry Bodin USFWS 27 Aug 86 Dr. Bruce Thompson LSU - CWR 28 Aug 86 Mr. Mike Schurtz DEQ 28 Aug 86 Mr. Dugan Sabins DEQ 28 Aug 86 Mr. John Tarver LDWF 29...Our Coast 15 Sep 86 Mr. Alfred Hitter, Jr. Save Our Coast 15 Sep 86 Mr. Pete Juneau LDWF 16 Sep 86 Mr. Gerry Bodin USFWS 16 Sep 86 Dr. Walter Sikora LSU...19 Sep 86 Dr. Jean Sikora LSU 19 Sep 86 Dr. Hinton Hoese USL 16 Oct 86 Dr. Daryl Felder USL 16 Oct 86 Mr. Michael Osborne Attorney 4 Dec 86 Mr

  16. The research of copper enrichment in four types of shellfish%4种海洋贝类对海水中铜(Cu)的富集能力

    Institute of Scientific and Technical Information of China (English)

    郭远明; 刘琴; 顾捷; 尤炬炬; 孙秀梅; 刘士忠

    2012-01-01

    为研究4种海洋贝类(泥蚶、菲律宾蛤仔、缢蛏、单齿螺)对海水中铜(Cu)的富集效应.设置Cu浓度分别为0.0l5、0.020、0.025、0.035、0.065和0.ll5mg/L 6个试验组,采用半静水法进行泥蚶、菲律宾蛤仔、缢蛏、单齿螺对海水中Cu的富集试验,分别在0、l、3、5、l0、15、20、25、30d取出部分贝类用微波消解一原子吸收光谱法测定Cu含量.结果表明:4种贝类均对Cu表现出了一定的富集效应,单壳类对Cu的富集效应明显大于双壳类.水体中Cu浓度达到0.035mg/L时,泥蚶和单齿螺对Cu的富集效应明显.水体中Cu浓度达到0.025mg/L时,菲律宾蛤仔和缢蛏对Cu富集明显.贝类体内Cu含量总体上随水体中Cu含量增加而增加,但当水体中Cu浓度在某个浓度点时,贝类体内的Cu含量反而有个低点.这一低点对于泥蚶为0.025mg/L、对于菲律宾蛤仔和单齿螺为0.035mg/L,缢蛏并不明显.贝类体内Cu含量总体上随富集时间的增加而增加.在3~5d时,贝类体内Cu含量明显降低,在5~10d后Cu含量又继续增加.同时,实验还进一步探讨了贝类对重金属的富集机制,比较了不同贝类对重金的富集能力.%The copper enrichment effects in four types of shellfish including Tegillarca granosa, Ruditapes philippinarum, Sinonovacula constricat canarck and Monodonta labio were studied in this paper. The study was carried out through the static test method. The shellfish was cultivated in seawater contaminated with different copper concentrations (0.015, 0.02, 0.025, 0.035, 0.065 and 0.115 mg/L, respectively). The content of Cu was analyzed in muscle tissue using atomic absorption spectrometry with microwave digestion in 0, 1, 3, 5, 10, 15, 20, 25 and 30 d, respectively. The results indicated that the four types of shellfish had copper enrichment effect. The concentration of copper in monoplacophora was higher than that in bivalvia. The copper content in T. granosa and M. labio exhibited

  17. Monitoring of Federally Threatened and Endangered Species on U.S. Army Installations

    Science.gov (United States)

    2004-12-01

    Clam E 0 1 0 Dipodomys stephensi Stephen’s Kangaroo Rat Mammal E 0 1 0 Dromus dromas Dromedary Pearlymussel Clam E 0 1 0 Epioblasma florentina...N Onsite Dromus dromas Dromedary Pearlymussel Clam E Contiguous Epioblasma florentina walkeri Tan Riffleshell Clam E Contiguous Myotis grisescens

  18. Fish and Wildlife Habitat Changes Resulting from Construction of a Nine-Foot Channel on Pools 24, 25, and 26 of the Mississippi River and the Lower Illinois River,

    Science.gov (United States)

    1979-04-01

    Sphaeriidae (fingernail clams) 10.4 52 35.4 19.4 Corbiculidae (Asiatic clams) 2.6 19.4 Unionidae (mussels) 1.0 1.1 Insecta (insects) Odonata ...fingernail clams) 2.4 3.5 Corbiculidae (Asiatic clams) 9.8 Unionidae (mussels) 0.1 Insecta (insects) Odonata (dragonflies) 0.1 Ephemeroptera...Trichoptera claws Polecypoda. Dobson flies Neuroptera Dragonflies Odonata Fingernail clan MgcjjJu. taneverui - Svhacriu transversu Fingernail clams

  19. Field and laboratory investigations of budding in the tetillid sponge Cinachyrella cavernosa

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, A.; Thakur, N.L.

    of the nutritional condition in juveniles of Ruditapes decussatus. Scientia marina 59: 95-101. Chu JW & Leys SP. 2010. High resolution mapping of community structure in three glass sponge reefs (Porifera, Hexactinellida). Marine Ecology Progress Series 417: 97...

  20. Spectrophotometric Determination of Taurine in Shellfish Using Promoting Fuchsin Basic Oxidation%促进氧化碱性品红光度法测定贝类中牛磺酸

    Institute of Scientific and Technical Information of China (English)

    李咏梅; 祝龙生; 葛仁奎; 石妍妍; 谭超兰

    2013-01-01

    在pH 4.19盐酸-乙酸钠缓冲溶液中,痕量牛磺酸能促进高锰酸钾氧化碱性品红的反应,使体系吸光度明显增大,据此建立了分光光度法测定牛磺酸的新方法。最大吸收波长为400 nm,牛磺酸质量浓度在0~0.20 mg/L范围内符合比耳定律,表观摩尔吸光系数为4.97×105 L·mol-1·cm-1,检出限为4.79μg/L。方法用于测定文蛤、紫贻贝和菲律宾蛤仔中牛磺酸,结果与高效液相色谱法一致,标准偏差小于3%(n=6),回收率为99.0%~102.1%。该方法灵敏、准确、简便、快速,重现性和选择性好,反应条件温和,对环境友好,完全满足贝类中牛磺酸含量的检测要求。%A new spectrophotometric method for the determination of taurine was developed.The method was based on the promotive action of trace taurine with the reaction of potassium hyper-manganate oxidizing fuchsin basic in hydrochloric acid-sodium acetate buffer solution at pH 4.19. It resulted in great increase of absorbance.The maximum absorption wavelength was at 400 nm. The Beer’s law was obeyed in the range of 0-0.20 mg/L for taurine with the apparent molar ab-sorption coefficient of 4.97×105 L·mol-1 ·cm-1 ,and the detection limit was 4.79μg/L.This method was applied to the determination of taurine in Meretrixmeretrix,Mytilusedulis and Ru-ditapes philippinarum.The results agreed well with those obtained by the high performance liq-uid chromatography.The relative standard deviation was less than 3%(n=6 ),and the average recovery was 99.0%-102.1%.This method was sensitive,accurate,simple,rapid,reproduci-ble and selective.In addition,the method was friendly to environment for its mild reaction condi-tions,and it could completely satisfy the requirements for the analysis of taurine content in shellfish.

  1. Control of modiolid mussels in cooling water systems by continuous chlorination.

    NARCIS (Netherlands)

    Rajagopal, S.; Venugopalan, V.P.; Velde, G. van der; Jenner, H.A.

    2006-01-01

    Abstract. Modiolid mussels such as Modiolus philippinarum and Modiolus metcalfei constitute a numerically significant group in fouling communities, especially in tropical and subtropical industrial cooling water systems. Nevertheless, there are hardly any published reports on the tolerance of these

  2. Optical properties and toxicity of undoped and Mn-doped ZnS semiconductor nanoparticles synthesized through the aqueous route

    Science.gov (United States)

    Labiadh, Houcine; Sellami, Badreddine; Khazri, Abdelhafidh; Saidani, Wiem; Khemais, Said

    2017-02-01

    Undoped and Mn-doped ZnS nanoparticles were synthesized at 95 °C in basic aqueous solution using the nucleation-doping strategy. Various samples of the Mn:ZnS NPs with 5, 10 and 20% of Mn dopant have been prepared and characterized using X-ray diffraction, energy-dispersive X-ray analysis, high resolution electron microscopy and photoluminescence (PL) measurements. When increasing the concentration of manganese Mn, the photoluminescence intensity gradually decreases. The PL spectra of the Mn-doped ZnS nanoparticles at room temperature exhibit both, the 450 nm blue defect-related emission and the 592 nm orange Mn2+ emission. It is vital to obtain NPs that meet the application requirements, however their environmental toxicity needs to be investigated. In this study, the induction of oxidative stress within the digestive gland of the Ruditapes decussatus organism (clam) is described. Antioxidant enzyme activities (superoxide dismutase (SOD) and catalase (CAT)) as well as malondialdehyde (MDA) levels have been determined in the digestive gland after exposure to 100 μg/L of ZnS, ZnS:Mn (5%), ZnS:Mn (10%) and ZnS:Mn (20%). The nanomaterials studied exhibit different responses in the digestive gland. Undoped Mn-ZnS has no effect on the markers considered, showing the limited interaction between this nanoparticle and the cells of the test organisms. In contrast, Mn-doped ZnS increases the activities of SOD and CAT and the level of MDA species, although this toxicity is highly dependent on the chemical properties of the material. These findings provide ideas for future considerations of ZnS nanoparticles, as well as information on the interaction between these materials and an aquatic environment. These data are the first evidence available of the formation of ZnS NPs using aqueous method and are an indication of the importance of knowing the biological target of the NPs when testing their potential impact on environmental model organisms.

  3. Quantitative data analysis of chemical contamination in the Venice lagoon. A risk management perspective

    Energy Technology Data Exchange (ETDEWEB)

    Miniero, R.; Domenico, A. di [Istituto Superiore di Sanita, Rome (Italy). Dept. Environment and Primary Prevention

    2004-09-15

    A comprehensive risk management for the contaminants present in bottom sediments of the Venice lagoon appears to be complicated by three issues: the past, present, and future influence of human pressure; the obvious sensitivity of a wetland like the lagoon; its extension. The actual situation can be viewed as typical of stressors at regional scale. The relationships between a coastal city and its environment are one of the central question addressed in Chapter 17 of Agenda 21, adopted at the United Nations Conference on Environment and Development (UNCED). In this chapter, the importance of coasts in a life-supporting system and the positive opportunity for sustainable development that coastal areas represent are stressed. However, in industrialized countries a practicable co-existence of environment and development will require mostly regulatory measures to regulate their relationships. The Venice lagoon is one of the leading shellfish production areas in Italy, harvesting several metric tons per year of the clam Tapes philippinarum and the mussel Mytilus galloprovincialis. A number of studies in recent years have characterized the chemical contamination of matrices like biota and sediment. The chemicals analyzed belong to different families including organic contaminants (such as polychlorinated dibenzodioxins (PCDDs) and dibenzofurans (PCDFs)), chlorinated pesticides, heavy metals, organometals, etc. The primary contamination sources have been clearly identified with Porto Marghera industrial settlement and the city of Venice with its canals, motorboats, and dense anthropogenic activity. The impacts of all these activities appear to be concentrated in the central basin although the industrial area be situated at the southern boundaries of the northern basin. From the studies on sediments, the following four impact types were identified in the lagoon: industrial, urban, ''not classifiable'', and lagoon background. In this paper, the PCDD

  4. Effect of permethrin, anthracene and mixture exposure on shell components, enzymatic activities and proteins status in the Mediterranean clam Venerupis decussata.

    Science.gov (United States)

    Sellami, Badreddine; Khazri, Abdelhafidh; Mezni, Amine; Louati, Héla; Dellali, Mohamed; Aissa, Patricia; Mahmoudi, Ezzeddine; Beyrem, Hamouda; Sheehan, David

    2015-01-01

    Anthracene (ANT) and permethrin (PER) are two of the more toxic compounds reaching the marine environment. This study aimed to determine the impact of these molecules on Venerupis decussata, an economically important species cultured on the Tunisian coast. Shell structure and its possible transformation upon exposure to the two contaminants were studied by X-ray diffraction and gravimetric analyses. Results revealed a phase transition in shell composition from aragonite to calcite after PER exposure, to a mixture of PER and ANT (Mix) but not for ANT alone. Catalase (CAT), superoxide dismutase (SOD) and glutathione transferase (GST) activities were determined in digestive gland and gills after exposure to ANT, PER and Mix to assess the impact of the contamination on the oxidative status of V. decussata. Enzyme activities increased in the digestive gland after PER treatment and in the gills after ANT treatment. PER exposure significantly reduced the levels of free thiols and increased levels of carbonylated proteins in the digestive gland, as compared to controls. In contrast, ANT exposure significantly reduced free thiols and increased the number of carbonylated proteins in the gills. Mix induced additive effects as measured by both enzymatic and proteomic approaches. The present study suggests that PER has a strong effect on shell structure; that PER and ANT exposure generate compound-dependent oxidative stress in the tissues of V. decussata and that a mixture of the two compounds has synergistic effects on biochemical response.

  5. EXPOSURE ASSESSMENT TO FOOD CONTAMINANTS ON EDIBLE FISH, CLAMS AND CRUSTACEANS IN A COASTAL ENVIRONMENT FACING A MINING AND INDUSTRIAL AREA IN SARDINIA (SULCIS-IGLESIENTE

    Directory of Open Access Journals (Sweden)

    P.L. Piras

    2011-08-01

    Full Text Available The risk assessment following exposure of the local population to the consumption of fishery products caught in the Boi Cerbus lagoon, located in country of Portoscuso (Sardinia, followed the phase of sampling, analysis and data-collection “site-specific”. Overall, the fishery products samples are part of the following zoological groups: fish (grey mullets, soles and gobies, bivalve (cockles and crustaceans (crabs. It was also agreed that further investigation were implemented in a targeted way, directing attention to critical issues that emerged from the first phase, represented by heavy metals such as Cadmium, Lead, Mercury and the (metalloid Arsenic that, for the purposes of food safety, are still contaminants with high concern for the potential impact on human health. For the risk analysis through food intake, three different procedures for exposure assessment were considered: the regulation by law, the assessment according to US-EPA approach and the assessment according to EU harmonized method. For a wider opportunity for exposure assessment through ingestion of food from contaminated areas, also for their risk management, a single approach to the risk analysis is not be considered sufficient.

  6. Oxidative stress and histological changes following exposure to diamond nanoparticles in the freshwater Asian clam Corbicula fluminea (Müller, 1774)

    Energy Technology Data Exchange (ETDEWEB)

    Cid, Antonio [REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnología, Centro de Química Fina e Biotecnología, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Picado, Ana; Correia, José Brito [LNEG-Laboratório Nacional de Energia e Geologia, I.P. Estrada do Paço do Lumiar 22, 1649-038 Lisboa (Portugal); Chaves, Rúben; Silva, Héber [Centro de Investigação Interdisciplinar Egas Moniz, Instituto Superior de Ciências da Saúde Egas Moniz, 2825-511 Caparica (Portugal); Caldeira, Jorge [REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnología, Centro de Química Fina e Biotecnología, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Centro de Investigação Interdisciplinar Egas Moniz, Instituto Superior de Ciências da Saúde Egas Moniz, 2825-511 Caparica (Portugal); Alves de Matos, António P. [Centro de Investigação Interdisciplinar Egas Moniz, Instituto Superior de Ciências da Saúde Egas Moniz, 2825-511 Caparica (Portugal); Centro de Estudos do Ambiente e do Mar (CESAM/FCUL)—Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa (Portugal); and others

    2015-03-02

    Highlights: • We assess the toxicity of NDs in the bivalve Corbiculafluminea. • Exposure to NDs cause a stress oxidative response. • Stress oxidative enzymes increase following exposure to nanodiamonds. • Increase in lipid peroxidation suggests damage in cells membranes. • Histopathology reveals alterations in digestive gland cells. - Abstract: Recently, the scientific community became aware of the potential ability of nanoparticles to cause toxicity in living organisms. Therefore, many of the implications for aquatic ecosystems and its effects on living organisms are still to be evaluated and fully understood. In this study, the toxicity of nanodiamonds (NDs) was assessed in the freshwater bivalve (Corbicula fluminea) following exposure to different nominal concentrations of NDs (0.01, 0.1, 1, and 10 mg l{sup −1}) throughout 14 days. The NDs were characterized (gravimetry, pH, zeta potential, electron microscopy, and atomic force microscopy) confirming manufacturer information and showing NDs with a size of 4–6 nm. Oxidative stress enzymes activities (glutathione-S-transferase, catalase) and lipid peroxidation were determined. The results show a trend to increase in GST activities after seven days of exposure in bivalves exposed to NDs concentrations (>0.1 mg l{sup −1}), while for catalase a significant increase was found in bivalves exposed from 0.01 to 1.0 mg l{sup −1} following an exposure of 14 days. The histological analysis revealed alterations in digestive gland cells, such as vacuolization and thickening. The lipid peroxidation showed a trend to increase for the different tested NDs concentrations which is compatible with the observed cellular damage.

  7. 缢蛏育苗过程中几个问题的探讨%Several problems in propagation of razor clam (Sinonovacula constricta)

    Institute of Scientific and Technical Information of China (English)

    王冬群

    2004-01-01

    缢蛏(Sinonovacula constricta Lamarck)俗称蛏子(福建)、蜻子(浙江)、跣子(山东、河北和辽宁),隶属软体动物门(Mollusca)、瓣鳃纲(Lamelli-branchia)、真瓣鳃目(Eulamellibranchia)、竹蛏科(Solenidae),是我国养殖产量和面积最大的贝类之一,以前养殖缢蛏的苗种来自野生苗,但随着养殖面积的扩大,野生苗已远远不能满足生产的需要。

  8. First European record of the invasive brackish water clam Rangia cuneata (G.B. Sowerby I, 1831) (Mollusca: Bivalvia)

    OpenAIRE

    Verween, A; Kerckhof, F.; Vincx, M.; Degraer, S.

    2006-01-01

    A population of Rangia cuneata (G.B. Sowerby I, 1831), an estuarine bivalve, has been recorded in the harbour of Antwerp, Belgium. This species is new to the European brackish water fauna. After initially finding only a few small individuals in August 2005, R. cuneata was encountered frequently in the pipes of the cooling water system of an industrial plant from February 2006 onwards. Before this present record, R. cuneata was only known from the Gulf of Mexico and the Atlantic coast of North...

  9. Developing simple tools for transferring the biology to the management in small scale fisheries: the case of a sword razor clam fishery in Galicia

    Directory of Open Access Journals (Sweden)

    Alba Hernández Otero

    2014-06-01

    Fig. 2. Management procedure proposed. Dark grey polygons indicate the stakeholders involved in shellfishing. Light grey polygons and white boxes show the recommended management actions. Fig. 3 von Bertalanffy growth curves fitted for E. magnus using growth marks revealed in the acetate peels.

  10. Salinity-related growth rates in populations of the European clam Macoma balthica and in field transplant experiments along the Baltic Sea salinity gradient

    NARCIS (Netherlands)

    Jansen, J.M.; Koutstaal, A.; Bonga, S.W.; Hummel, H.

    2009-01-01

    Most benthic invertebrates and plant species that survive in the brackish Baltic Sea are characterized by populations in which growth is reduced and genetic diversity is low, indicating that these species live under marginal conditions. In this study, we tested for a salinity-related growth rate red

  11. Bio-accumulation of copper, zinc, iron and manganese in oyster Saccostrea cucullata, Snail Cerithium rubus and Clam Tellina angulata from the Bombay coast

    Digital Repository Service at National Institute of Oceanography (India)

    Krishnakumari, L.; Nair, V.R.; Moraes, C.

    and C. rubus. Sexwise, iron content was high in male and manganese in female oysters. In T. angulata male specimens showed maximum zinc content. Stationwise, difference in copper and iron was significant in C. rubus. In general, copper and zinc...

  12. Influence of form IA RubisCO and environmental dissolved inorganic carbon on the delta13C of the clam-chemoautotroph symbiosis Solemya velum.

    Science.gov (United States)

    Scott, Kathleen M; Schwedock, Julie; Schrag, Daniel P; Cavanaugh, Colleen M

    2004-12-01

    Many nutritive symbioses between chemoautotrophic bacteria and invertebrates, such as Solemya velum, have delta(13)C values of approximately -30 to -35%, considerably more depleted than phytoplankton. Most of the chemoautotrophic symbionts fix carbon with a form IA ribulose 1,5-bisphosphate carboxylase (RubisCO). We hypothesized that this form of RubisCO discriminates against (13)CO(2) to a greater extent than other forms. Solemya velum symbiont RubisCO was cloned and expressed in Escherichia coli, purified and characterized. Enzyme from this recombinant system fixed carbon most rapidly at pH 7.5 and 20-25 degrees C. Surprisingly, this RubisCO had an epsilon-value (proportional to the degree to which the enzyme discriminates against (13)CO(2)) of 24.4 per thousand, similar to form IB RubisCOs, and higher than form II RubisCOs. Samples of interstitial water from S. velum's habitat were collected to determine whether the dissolved inorganic carbon (DIC) could contribute to the negative delta(13)C values. Solemya velum habitat DIC was present at high concentrations (up to approximately 5 mM) and isotopically depleted, with delta(13)C values as low as approximately -6%. Thus environmental DIC, coupled with a high degree of isotopic fractionation by symbiont RubisCO likely contribute to the isotopically depleted delta(13)C values of S. velum biomass, highlighting the necessity of considering factors at all levels (from environmental to enzymatic) in interpreting stable isotope ratios.

  13. 奥尔森帕金虫环介导等温扩增(LAMP)检测方法的建立及应用%Establishment and application of a loop-mediated isothermal amplification (LAMP) method for Perkinsus olseni detection

    Institute of Scientific and Technical Information of China (English)

    曲朋; 王崇明; 任伟成; 梁彦韬; 贾志磊; 黄倢; 潘鲁青

    2012-01-01

    Perkinsus olseni(P. olseni) is one of the important pathogenic parasites of the shellfish. With the purpose of building a rapid, sensitive, accurate and easy to use detection method for P. olseni, we established a P. olseni loop-mediated isothermal amplification assay(LAMP) based on the internal transcribed spacer(ITS) of Perkinsus olseni 5.8S rDNA sequences. We used the online software Primer Explorer V4 (http://primerexplorer.jp/e/) and designed a set of 4 LAMP primers(Perk-FIP, Perk-BIP, Perk-F3 and Perk-B3) of the P. olseni, then we optimized the reaction conditions, mainly about the reaction temperature, magnesium ion concentration of the reaction system and the reaction time. After that, we got the P. olseni 25 uL LAMP reaction system, including: 2.5 μL l0×ThermoPol Reaction Buffer, 4 μL dNTPs(10 mmol/L each), 5 μL Betaine(5 mol/L), 1.6 uL Perk-FIP(25 umol/L), 1.6 μL Perk-BIP(25 umol/L), 1 μL Perk-B3(5 umol/L), 1 uL Perk-F3(5 umol/L), 4 uL MgCl2(25 mmol/L), 2.3 uL sterile water, 1 μL Bst DNA poly-merse(8 000 U/mL) and 1 μL DNA template, the optimal reaction temperature is 64 ℃ and the optimal reaction time is 60 min. In this research, the LAMP products were detected mainly using agarose gel electrophoresis and visual inspection of a color change due to addition of fluorescent dye. Before confirming the minimum threshold of the LAMP, we constructed P. olseni positive plasmid, also based on P. olseni 5.8S rDNA ITS sequences. The result shows that the minimum threshold of the LAMP assay is approximately 30 copies of plasmid DNA. We proved that the developed LAMP method was highly specific for P. olseni, and no cross-reaction was observed with other pathogens, such as Perkinsus marinus{P. marinus), Bonamia exitiosa(B. exitiosa), Ichthyobodo sp. and Acute Viral Necrosis Virus(AVNV). A comparative evaluation of the LAMP and PCR assays using 20 Ruditapes philippinarum(R. philippinarum) samples showed that LAMP is more sensitive and accurate than PCR and

  14. Comparative feeding on chlorophyll - rich versus remaining organic matter in bivalve shellfish

    NARCIS (Netherlands)

    Hawkins, A.; Pascoe, P.L.; Parry, H.; Brinsley, M.; Cacciatore, F.; Black, K.; Fang, J.; Smaal, A.C.

    2013-01-01

    Filter feeding was compared in the blue mussel Mytilus edulis, Mediterranean mussel Mytilus galloprovincialis, Pacific oyster Crassostrea gigas, Chinese pleated oyster Crassostrea plicatula, Chinese scallop Chlamys farreri,Manila clam Tapes phillipinarum, razor clam Sinonvacula constricta, and blood

  15. The impact of ocean acidification on the early life stages of surf clams and the interactive effects of feeding and temperature from laboratory experiment studies from 2011-07-12 to 2012-06-17 (NODC Accession 0123314)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains laboratory experiment data that were collected to examine the effects of ocean acidification on the Atlantic surfclam, Spisula...

  16. 车螺肉酶解液中提取分离天然牛磺酸工艺%Extraction and Separation of Natural Taurine from Enzymatic Hydrolysis Water of Marine Clam Meat

    Institute of Scientific and Technical Information of China (English)

    粟桂娇; 阎欲晓; 覃洁; 黄艳萍; 聂桂锋

    2005-01-01

    以新鲜车螺肉为原料,采用酸性蛋白酶先酶解再水煮工艺提取天然牛磺酸.在料:水=1:3(W/V),酶解温度35℃,酶解pH2.5前提下,酸性蛋白酶最适的提取条件为加酶量E/S=2000U/g,酶解时间4h,水煮时间0.5h.用H+型强酸性阳离子交换树脂从酶解提取液中分离提纯牛磺酸,结果表明该工艺能有效地将牛磺酸与甘氨酸、赖氨酸等其他氨基酸分离.在25×400(mm)离子交换柱湿装柱量为120ml,洗脱速度1.5BV/h条件下,最适上柱量0.5mg氨基氮/ml湿树脂,在pH0.9~3.3范围内的洗脱液是牛磺酸流出的高流分部分.

  17. 基于CO Ⅰ的中国西施舌DNA条形码%DNA Barcodes of Clam Coelomactata antiquata (Bivalvia: Veneroida)in China Based on CO Ⅰ Gene

    Institute of Scientific and Technical Information of China (English)

    孟学平; 高如承; 申欣; 郑雯雯; 赵娜娜; 程汉良; 田美

    2011-01-01

    以我国大连(DL)、日照(RZ)、启东(QD)、长乐(CL)、漳州(ZZ)和北海(BH)6个野生群体西施舌为研究对象,用引物LCO1490和HCO2198扩增线粒体细胞色素C氧化酶亚基Ⅰ(COⅠ)基因片段序列,PCR产物双向测序,用ClustalX进行DNA序列比对,用MEGA4.1和PhyML软件构建NJ树和ML树,用Arlequin3.11软件进行分子方差分析,研究CO Ⅰ这一特定基因区段作为DNA条形码在识别西施舌地理群体的可行性和有效性.结果获得658 bp的CO Ⅰ核苷酸片段,其T、C、A、G含量分别为42.4%、14.8%、21.8%、21.0%,A+T(64.2%)含量明显高于G+C含量.变异位点占15.3%(101/658),其中简约信息位点占14.1%.群体内遗传距离为0.0020~0.0043,群体间遗传距离为0.0024~0.0883.群体间氨基酸序列无变异.长乐、漳州群体(DH组)与其他群体(HB组)间有显著的遗传分化(FST=0.956~0.970).NJ树和ML树显示长乐、漳州群体聚为一支,北方的大连、日照、启东群体和南方的北海群体聚为置信度较高的另一支(BPN=99),2支间的遗传距离为0.0837,是2支内群体间遗传距离的17.8~23.5倍.本研究结果表明,CO Ⅰ基因片段序列作为鉴定福建西施舌条形码是可行的,但不能将其余群体区别开来.

  18. Sequence analysis of the ribosomal DNA internal transcribed spacer region in some clam species (Mollusca: Bivalvia: Veneroida)%几种帘形目贝类rDNA ITS序列的比较

    Institute of Scientific and Technical Information of China (English)

    刘相全; 包振民; 胡景杰; 王师; 方建光; 王如才

    2007-01-01

    扩增并测序了4种帘形目和1种蚶目贝类(外群)核糖体DNA的转录间隔区(ITS)序列.帘形目贝类序列长度在874bp到1466bp之间,GC含量在62%到67%之间,ITS序列在相近的3种帘蛤科贝类之间表现出长度保守性和碱基组成的相似性.采用ITS1,ITS2,以及ITS1与ITS2的连接序列进行聚类,结果表明:2种蛤仔聚为一枝,表现出较近的亲缘关系,帘蛤科的3种贝类聚在一起,再与同属帘形目的缢蛏相聚.研究的结果揭示了帘形目贝类的系统发生关系.

  19. TOXIC EFFECT OF COPPER, ZINC, LEAD AND CADMIUM ON SPERM OF RAZOR CLAM (SINONOVACULA CONSTRICAT CANARCK)%重金属对滩涂贝类缢蛏精子的毒性作用

    Institute of Scientific and Technical Information of China (English)

    刘广绪; 吴洪喜; 柴雪良; 邵艳卿; 刘伟成; 林志华

    2011-01-01

    @@ 相对于有机污染物而言, 重金属污染物具有高毒性、高稳定性、能通过食物链富集以及直接影响被污染生物生殖繁育的特点, 因而引起了人们的广大关注[1, 2].随着过去几十年来工业的迅速发展, 大量人为重金属污染物被释放到海洋与河口环境, 海洋沿岸滩涂区域成为重金属沉积的主要区域之一, 对沿岸滩涂生物例如滩涂贝类造成了巨大的威胁.

  20. Industrial trial of ecological culture of Venus clam Cyclina sinensis in the Yellow River Delta%黄河三角洲青蛤产业化生态养殖试验

    Institute of Scientific and Technical Information of China (English)

    张洪欣; 明秀云; 张洪勋; 刘志海

    2006-01-01

    青蛤[Cyclina sinensis(Gmelin)],属于软体动物门(Mollusca)、双壳纲(Bivalvia)[以前也被称为瓣鳃纲(Lamellibranchiata)]、真瓣鳃目(Eulamellibranchia),帘蛤科(Veneridae)、青蛤属(Cyclinasinensis),俗称蛤蜊、圆蛤、墨蛤,为暖水性种类,我国南北沿海均有分布,主要产区有山东、辽宁、河北、江苏等地,尤其是黄河三角洲沿岸的优势品种。它肉嫩味鲜,营养丰富,含有多种人体所需的微量元素,素有“天下第二鲜”的美称。除鲜食外,

  1. Be/CLAM钢热等静压连接界面特性及力学性能%Interface Characteristic and Mechanical Property of Diffusion Bonding on Be/CLAM Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    冷邦义; 鲜晓斌; 罗德礼; 谢茂林; 黄火根; 蓝林钢

    2008-01-01

    以AgCu28合金作为过渡层材料,采用热等静压(HIP)方法进行Be/CLAM钢(中国低活化马氏体钢)的扩散连接.利用扫描电镜(SEM)、能谱仪(EDS)及剪切试验分析了接头的扩散层显微组织、元素分布和力学性能.研究表明:采用AgCu28合金作为过渡层材料,在900℃,160 MPa,2 h条件下能够实现Be/CLAM钢的扩散连接;Agcu28合金过渡层材料能有效地减少铍、CLAM钢母材间的元素互扩散,防止了Be-Fe等脆性金属间化合物的大量生成.接头质量较好,剪切强度达180 MPa.

  2. Using Passive Polyethylene Samplers to Evaluate Chemical Activities Controlling Fluxes and Bioaccumulation of Organic Contaminants in Bed Sediments

    Science.gov (United States)

    2010-11-01

    carbon sorbents such as soots, biomass chars , and coal residues, and these components of the “foc” must 2 be specifically treated to estimate Kd... Partially thawed clams were measured for shell length and whole-clam mass. Clams were then shucked, reweighed, and dissected to remove stomach...we assume all soots, chars , coals, etc. exhibit identical carbon mass- normalized adsorption parameters. Nonetheless, this exercise indicates that

  3. 76 FR 65698 - Magnuson-Stevens Act Provisions; General Provisions for Domestic Fisheries; Application for...

    Science.gov (United States)

    2011-10-24

    ... mailbox address for providing e-mail comments is NERO.EFP@noaa.gov . Include in the subject line of the e..., Gloucester, MA 01930, and are available via the Internet at http://www.nero.noaa.gov/sfd/clams . FOR FURTHER... available from the NMFS Northeast Region Web site: http://www.nero.noaa.gov/sfd/clams . This project is...

  4. 75 FR 66070 - Magnuson-Stevens Act Provisions; General Provisions for Domestic Fisheries; Application for...

    Science.gov (United States)

    2010-10-27

    ... mailbox address for providing e-mail comments is NERO.EFP@noaa.gov . Include in the subject line of the e... available via the Internet at http://www.nero.noaa.gov/sfd/clams . SUPPLEMENTARY INFORMATION: The applicant... Northeast Region Web site: http://www.nero.noaa.gov/sfd/clams . The proposed project would continue...

  5. 50 CFR 648.74 - Shucking at sea.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Shucking at sea. 648.74 Section 648.74... Clam and Ocean Quahog Fisheries § 648.74 Shucking at sea. (a) Observers. (1) The Regional Administrator may allow the shucking of surf clams or ocean quahogs at sea if he/she determines that an...

  6. Threatened and Endangered Species on Army Installations: A MACOM Report.

    Science.gov (United States)

    1997-12-01

    ONSrrE AND CONTIGUOUS Birds Peregrine Falcon, Falco peregrinus E(S/A) Bald Eagle, Haliaeetus leucocephalus (T) CONTIGUOUS Clams Dromedary Pearly Mussel...Reservation USARPAC Dromus dromas Dromedary Pearly Mussel (E) Clam Ft. Campbell FORSCOM USACERL TR-98/18 93 Drymarchon corais couperi Eastern Indigo

  7. Anoxic survival of Macoma balthica: the effect of antibiotics, molybdate and sulphide

    NARCIS (Netherlands)

    De Zwaan, A.; Schaub, B.; Babarro, J.M.F.

    2001-01-01

    In anoxic semi-closed systems, the survival time of the clam Macoma balthica was compared to clams which were incubated in the presence of several antibiotics (chloramphenicol, 5- oxytetracycline hydrochloride, penicillin, streptomycin. a mix of penicillin and streptomycin and a mix of chloramphenic

  8. 50 CFR 600.725 - General prohibitions.

    Science.gov (United States)

    2010-10-01

    .... Rod and reel, handline, pot, spear. 11. Surf Clam and Ocean Quahog Fishery (FMP managed by the MAFMC... fishery I. Rod and reel, handline, pot, spear. 4. Surf Clam and Ocean Quahog Fishery (FMP): A. Commercial... fishery A. Trap, pot B. Recreational fishery B. Trap, pot, hand harvest. 7. Blue Crab Fishery...

  9. 76 FR 15841 - Irradiation in the Production, Processing, and Handling of Food; Confirmation of Effective Date

    Science.gov (United States)

    2011-03-22

    ... justifies use of a different safety factor, a safety factor in applying animal experimentation data to man... Objections and Response to Hearing Requests A. Studies on Animals Fed Clams B. Microbiological Safety of... for granting a hearing in Sec. 12.24(b) as follows:. A. Studies on Animals Fed Clams One...

  10. 50 CFR 648.73 - Closed areas.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Closed areas. 648.73 Section 648.73... Clam and Ocean Quahog Fisheries § 648.73 Closed areas. (a) Areas closed because of environmental degradation. Certain areas are closed to all surf clam and ocean quahog fishing because of...

  11. Extremely Low Frequency (ELF) Communications System Ecological Monitoring Program: Summary of 1983 Progress.

    Science.gov (United States)

    1984-07-01

    47 5. REFERENCES ................ ..... • •0• .................. Appendix A. Wildlife Surveys at Clam Lake ...field studies performed at University of Wisconsin-Parkside, at Kenosha, Wisconsin, and at Clam Lake , Wisconsin respectively. IiT RESEARCH INSTITUTE 15...typical clumped distri- bution for the organisms. Mites and collembola are numerically dominant, and few groups show a preference for either litter

  12. 77 FR 5492 - Magnuson-Stevens Act Provisions; General Provisions for Domestic Fisheries; Application for...

    Science.gov (United States)

    2012-02-03

    ... providing email comments is NERO.EFP@noaa.gov . Include in the subject line of the email comment the..., and are available via the Internet at www.nero.noaa.gov/sfd/clams . FOR FURTHER INFORMATION...

  13. Environmental contaminants in fish and wildlife of Havasu National Wildlife Refuge, Arizona

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Sediment, vegetation, clams, fish, waterbirds and waterbird eggs were collected at Havasu National Wildlife Refuge (NWR) during April-August 1993 for organochlorine...

  14. Sensitivity of Coastal Environments and Wildlife to Spilled Oil: Puget Sound and Strait of Juan de Fuca, Washington: INVERT (Invertebrate Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for clams, oysters, crabs, and other invertebrate species in Puget Sound and Strait of Juan de Fuca,...

  15. Corbiculae fluminea as a bioindicator on the Lower Colorado River

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Tissue samples from Asiatic clam (Corbimla fluminea) from the lower Colorado River were analyzed for trace element concentrations. Selenium and arsenic were elevated...

  16. Columbia River ESI: INVERT (Invertebrate Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for clams, oysters, crabs, and other invertebrate species in Columbia River. Vector polygons in this data...

  17. Vitamin B12

    Science.gov (United States)

    ... fortified. You can get the recommended amounts of vitamin B12 by eating a variety of the foods including: Organ meats (beef liver) Shellfish (clams) Meat, poultry, eggs, milk and other dairy foods Some breakfast cereals and ...

  18. Environmental impact assessment of benthic community stability in an estuarine complex

    Digital Repository Service at National Institute of Oceanography (India)

    Ansari, Z.A.; Abidi, S.A.H.

    . There was also a substantial decrease in clam production during the 10 year time under consideration. The implication of ever increasing mining rejects in the estuarine system and the utilization of quantitative benthic parameters in environmental impact studies...

  19. SC/OQ Vessel Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data tables holding information for the Surf Clam/Ocean Quahog vessel and dealer/processor logbooks (negative and positive), as well as individual tag information...

  20. Incidence and Management Costs of Freshwater Aquatic Nuisance Species at Projects Operated by the U.S. Army Corps of Engineers

    Science.gov (United States)

    2010-07-01

    the occurrence of ANS impacts (Yes or No) from freshwater algae, large aquatic plants, fish , zebra mussels, Asiatic clams, water fleas, crayfish...investment in research and development, especially for nuisance aquatic plants, fresh- water clams, and certain invasive fish species. Even so, aggregate...water hyacinths, hydrilla, common reed, sea lamprey, and the zebra mussel are especially notorious for their costly impacts on freshwater services

  1. 25 Years Later: A History of the McClellan-Kerr Arkansas River Navigation System in Arkansas

    Science.gov (United States)

    1995-01-01

    all of whom assist in its operation and maintenance, have given generously of their time to assist the author in writing this book. Judy ...activities. This instability created ideal conditions for an Asian clam, CorbicuLa, (also called " zebra mussel") that first appeared in the United...26, 31.46 Comet 4 Corbicula 60. See also zebra mussel: Asian clam Cotton Belt Railroad 77 Critical Path Method 35 Crockett Addition. North

  2. Extremely Low Frequency (ELF) Communications System Ecological Monitoring Program. Summary of 1984 Progress.

    Science.gov (United States)

    1985-07-01

    at Clam Lake , Wisconsin ;1. lIT RESEARCH INSTITUTE vii IITRI E06549-18 12 ] LIST OF FIGURES Page 1. ELF Communications Facilities in Wisconsin and...Monitoring Program. The completed transmitter will consist of two facilities, one located in the Chequamegon National Forest near Clam Lake , Wisconsin...with taxon (e.g., > 5x for carabids, > 2x for Collembola ). Previous estimates of surface-active fauna must therefore be interpreted with caution

  3. ELF Communications System, Ecological Monitoring Program: Summary of 1989 Progress

    Science.gov (United States)

    1990-11-01

    J.; Calandriano, F. J. An annotated list and new species descriptions of Collembola found In the Project ELF study area of Michigan. Great Lakes ...studies at the Naval Radio Transmitting Facility (NRTF)- Clam Lake , Wisconsin. was completed, as scheduled, during 1939. Data collection for studies at...facility is designated as the Naval Radio Transmitting Facility (NRTF)-Clam Lake , and the facility in Michigan as the NRTF-Republic. Each facility

  4. Gulf Coast Deep Water Port Facilities Study. Appendix D. Adverse Environmental Effects.

    Science.gov (United States)

    1973-04-01

    Gulf of mexico, Vol. 3. Chapter 2. In. Rezak and Henry. (eds). Gulf Publishing Co., 1971. Breuer, J.P., "An Ecological Survey of the Lower Laguna Madre ...marshplants Bay margin marine grass, clams, snails and blue crab Grass flats marine grass, clams, snails, black drum and t other fish Open bay with tidal...atlas project unfortunately only covers the Texas shoreline. At present, detailed information similar to that for Houston-Galveston is not available

  5. Grays Harbor and Chehalis River Improvements to Navigation Environmental Studies. Grays Harbor Ocean Disposal Study. Literature Review and Preliminary Benthic Sampling,

    Science.gov (United States)

    1980-05-01

    i l . .. ..... .. .. .- .... .. ... ... . . . ... ....-.. .. . ... . .L 44 and echinoderms . Large-mouth flounders and halibuts feed essentially...B. latifrons, S. fossor and the echinoderms l eiOphiura lutkeni and A.,phipholis sp. 66 Razor Clams An intensive razor clam sport fishery occurs on...Distribution of the Echinoderms off the Northern Oregon Coast," The Columbia River and Adjacent Ocean Waters, Bioenvironmental Stuaies, 1972, pp 475-537

  6. Biomonitoring and assessment of monomethylmercury exposure in aqueous systems using the DGT technique

    Energy Technology Data Exchange (ETDEWEB)

    Clarisse, O., E-mail: olivier.clarisse@umoncton.ca [Trent University, Chemistry Department, 1600 West Bank Drive, Peterborough, ON K9J 7B8 (Canada); Universite de Moncton, Departement de Chimie et de Biochimie, Moncton, New Brunswick E1A 3E9 (Canada); Lotufo, G.R. [Environmental Laboratory, U.S. Army Engineer Research and Development Center, Vicksburg, MS 39180-6199 (United States); Hintelmann, H. [Trent University, Chemistry Department, 1600 West Bank Drive, Peterborough, ON K9J 7B8 (Canada); Best, E.P.H. [Environmental Laboratory, U.S. Army Engineer Research and Development Center, Vicksburg, MS 39180-6199 (United States); U.S. Environmental Protection Agency, National Risk Management Research Laboratory, 26 West Martin Luther King Boulevard, Cincinnati, OH 45268 (United States)

    2012-02-01

    A series of laboratory experiments was conducted under realistic environmental conditions to test the ability of the Diffusive Gradient in Thin film (DGT) technique to mimic monomethylmercury (MMHg) bioaccumulation by a clam (Macoma balthica, Baltic clam). Using isotope enriched MMHg as tracers, bioavailability was determined by comparing the rate of MMHg uptake by novel DGT devices and sentinel organism over time. Experiments were conducted under varying conditions of salinity and MMHg speciation. Depending on MMHg level and speciation in the dissolved phase, MMHg uptake rates by the sentinel organism varied greatly from 0.4 to 2.4 L g{sup -1} d{sup -1}. Reproducibilities of MMHg uptakes by DGT and clams were estimated at 7 and 38%, respectively. A significant linear relationship (log basis) between MMHg accumulation by DGT and clams was observed (r{sup 2} = 0.89). The study demonstrates that DGT results reasonably predict MMHg uptake by clams from the aqueous phase and provide the basis for application of the DGT device as a surrogate for sentinel organism for monitoring bioavailable MMHg. - Highlights: Black-Right-Pointing-Pointer We investigate the potential of DGT devices to act as surrogates for sentinel organism. Black-Right-Pointing-Pointer We compare monomethylmercury accumulation in DGT devices and in clams from the dissolved phase. Black-Right-Pointing-Pointer We examine the effects of salinity and MMHg speciation on MMHg accumulation by DGT and clams. Black-Right-Pointing-Pointer For all laboratory experiments, a strong overall correlation between MMHg accumulations in clams and DGTs is observed.

  7. Mercury accumulation in caged Corbicula: rate of uptake and seasonal variation.

    Science.gov (United States)

    Neufeld, Douglas S G

    2010-09-01

    The uptake and seasonal fluctuations of total mercury were followed in caged and uncaged Asiatic clams, Corbicula fluminea, over a 1-year period in South River, Virginia. Mercury was rapidly accumulated in clams transplanted from a nominally uncontaminated site into cages on the contaminated South River, reaching 0.99 microg g(-1) dry mass within the first month. Resident clams moved to cages had higher mercury contents after the first month (2.04 microg g(-1) dry mass) and at all subsequent times in the study. Large monthly fluctuations in mercury were noted for both resident caged and transplant caged clams with a notable peak occurring in early spring (4.31 microg g(-1) dry mass in resident caged clams). Tissue mass of caged clams steadily increased through the winter and early spring. Adjustment of mercury concentrations for tissue mass changes indicated that the changes in mercury contents were primarily due to uptake/release rather than changes in tissue mass (concentration/dilution). The present study demonstrates the utility of using caged Corbicula as mercury biomonitors and illustrates the importance of accounting for large, short-term changes of mercury content in Corbicula when designing long-term biomonitoring studies.

  8. Biological uptake of polychlorinated biphenyls by Macoma balthica from sediment amended with activated carbon

    Science.gov (United States)

    McLeod, Pamela B.; van den Heuvel-Greve, Martine J.; Luoma, S.N.; Luthy, R.G.

    2007-01-01

    This work characterizes the efficacy of activated carbon amendment in reducing polychlorinated biphenyl (PCB) bioavailability to clams (Macoma balthica) from field-contaminated sediment (Hunters Point Naval Shipyard, San Francisco Bay, CA, USA) Test methods were developed for the use of clams to investigate the effects of sediment amendment on biological uptake. Sediment was mixed with activated carbon for one month. Bioaccumulation tests (28 d) were employed to assess the relationships between carbon dose and carbon particle size on observed reductions in clam biological uptake of PCBs. Extraction and cleanup protocols were developed for the clam tissue. Efficacy of activated carbon treatment was found to increase with both increasing carbon dose and decreasing carbon particle size. Average reductions in bioaccumulation of 22, 64, and 84% relative to untreated Hunters Point sediment were observed for carbon amendments of 0.34, 1.7, and 3.4%, respectively. Average bioaccumulation reductions of 41, 73, and 89% were observed for amendments (dose = 1.7% dry wt) with carbon particles of 180 to 250, 75 to 180, and 25 to 75 ??m, respectively, in diameter, indicating kinetic phenomena in these tests. Additionally, a biodynamic model quantifying clam PCB uptake from water and sediment as well as loss through elimination provided a good fit of experimental data. Model predictions suggest that the sediment ingestion route contributed 80 to 95% of the PCB burdens in the clams. ?? 2007 SETAC.

  9. Effects of starvation and refeeding on larval growth, survival, and metamorphosis of clam Cyclina sinensis%饥饿和再投喂对青蛤(Cyclina sinensis)幼虫生长、存活及变态的影响

    Institute of Scientific and Technical Information of China (English)

    杨凤; 张跃环; 闫喜武; 张国范

    2008-01-01

    在温度18.2~20.6℃,盐度23~25,pH 7.96~8.14 的条件下,研究了饥饿和再投喂对青蛤幼虫生长、存活及变态的影响.结果表明:在饥饿状态下,幼虫具有生长现象,且随着饥饿时间的延长,壳长逐渐接近一个常值而不再生长;幼虫可以由面盘幼虫发育到足面盘幼虫.随饥饿时间延长存活率下降;且足面盘幼虫及其变态规格、单水管稚贝规格随着饥饿时间延长而减小;幼虫的不可逆点(PNR)为12.48d;延迟变态时间长达12.7d.饥饿后再投喂相同的时间,幼虫能够恢复生长,存活的幼虫能够变态;稚贝表现出补偿生长现象,以壳长作为衡量标准,完全补偿生长能力依次为:S10>S11>S12>S1>S2>S3;超补偿生长能力依次为:S9>S8>S7>S6>S5>S4.

  10. A non-native prey mediates the effects of a shared predator on an ecosystem service.

    Directory of Open Access Journals (Sweden)

    James E Byers

    Full Text Available Non-native species can alter ecosystem functions performed by native species often by displacing influential native species. However, little is known about how ecosystem functions may be modified by trait-mediated indirect effects of non-native species. Oysters and other reef-associated filter feeders enhance water quality by controlling nutrients and contaminants in many estuarine environments. However, this ecosystem service may be mitigated by predation, competition, or other species interactions, especially when such interactions involve non-native species that share little evolutionary history. We assessed trophic and other interference effects on the critical ecosystem service of water filtration in mesocosm experiments. In single-species trials, typical field densities of oysters (Crassostrea virginica reduced water-column chlorophyll a more strongly than clams (Mercenaria mercenaria. The non-native filter-feeding reef crab Petrolisthes armatus did not draw down chlorophyll a. In multi-species treatments, oysters and clams combined additively to influence chlorophyll a drawdown. Petrolisthes did not affect net filtration when added to the bivalve-only treatments. Addition of the predatory mud crab Panopeus herbstii did not influence oyster feeding rates, but it did stop chlorophyll a drawdown by clams. However, when Petrolisthes was also added in with the clams, the clams filtered at their previously unadulterated rates, possibly because Petrolisthes drew the focus of predators or habituated the clams to crab stimuli. In sum, oysters were the most influential filter feeder, and neither predators nor competitors interfered with their net effect on water-column chlorophyll. In contrast, clams filtered less, but were more sensitive to predators as well as a facilitative buffering effect of Petrolisthes, illustrating that non-native species can indirectly affect an ecosystem service by aiding the performance of a native species.

  11. Nutritional value of winter foods for whooping cranes

    Science.gov (United States)

    Nelson, J.T.; Slack, R.D.; Gee, G.F.

    1996-01-01

    We measured metabolizable energy and digestibility of Whooping Crane (Grus americana) winter foods (blue crab [Callinectes sapidus]), common Rangia clam (Rangia cuneata), wolfberry fruit (Lycium carolinianurn [wolfberry]), and live oak acorn (Ouercus virginiana [acorn])] with feeding trials to captive-reared Whooping Cranes. Apparent metabolizable energy coefficients (expressed as %) were for crab (34.1), Rangia clam (75.0), wolfberry (44.8), and acorn (43.2). Digestion coefficients for protein were lower for plant foods (48.9 and 53.4) than for animal foods (69.4 and 75.2). Digestion coefficients for total lipid differed among foods: highest and lowest lipid digestibility was for acorn (87.2) and wolfberry (60.0), respectively. We also determined total energy and percent protein and lipid of the four foods and stout razor clam (Tagelus plebeius); gross energy was 2-5x higher for acorn and wolfberry on a dry-weight basis than for blue crab and stout razor clam. Crude protein was 2-3x higher for blue crab than for wolfberry and stout razor clam. Wolfberry ranked the highest of five foods for metabolic energy and total lipid nutrient availability per kg of food ingested, and blue crab ranked highest for crude protein availability.

  12. Relationships between environmental factors and Donax denticulatus populations in Puerto Rico

    Science.gov (United States)

    Sastre, Miguel P.

    1984-08-01

    Donax denticulatus population density and size distribution were studied in five different Puerto Rican beaches for a one year period in order to determine relationships between the densities and size distributions of the clam, and twelve different physico-chemical parameters of sediments and water. Maní beach exhibits significantly higher population densities followed by Luquillo, Esperanza and Ballenas. No clams were found in Crashboat. Luquillo and Esperanza had similar population fluctuations, having peak densities in August and January. Maní had higher densities in September and May, and Ballenas in June. The only major settlement period appeared during January at Esperanza. The bigger clams (30 mm) were found in Maní only. Higher population density and bigger clams in Maní are related to waters having high concentrations of total organic carbon, particulate organic carbon and nitrates. The clam was absent from Crashboat where very low levels of phosphates and nitrates were observed. These studies indicate relationships between water and sediment quality, and densities of D. denticulatus.

  13. Sea otter studies in Glacier Bay National Park and Preserve: annual report 2002

    Science.gov (United States)

    Bodkin, James L.; Kloecker, Kimberly A.; Esslinger, George G.; Monson, Daniel H.; Coletti, Heather A.; Doherty, Janet

    2003-01-01

    Since 1995, the number of sea otters in Glacier Bay proper has increased from around 5 to more than 1200. Sea otter distribution is mostly limited to the Lower Bay, south of Sandy Cove, and is not continuous within that area. Concentrations occur in the vicinity of Sita Reef and Boulder Island and between Pt. Carolus and Rush Pt. on the west side of the Bay, although there have been occasional sightings north of Sandy Cove (Figure 1). Large portions of the Bay remain unoccupied by sea otters, but recolonization is occurring rapidly. Most prey recovered by sea otters in Glacier Bay are ecologically, commercially, or socially important species. In 2002 sea otter diet consisted of 35% clam, 26% mussel, 3% crab, 3.0% snail, 2% starfish, 11% urchins, 2% other, and 20% unidentified. Dominant clam species include the butter clam, Saxidomus gigantea, the Greenland cockle, Serripes groenlandicus, and the littleneck clam, Protothaca staminea. Urchins are primarily green urchins, Strongylocentrotus droebachiensis, and the mussel is Modiolus modiolus. Crabs observed in 2002 include the Dungeness, Cancer magister, the kelp crab Pugettia gracilis, and the helmet crab, Telmessus cherigonus. Although we characterize diet at broad geographic scales, we have previously found diet to vary between sites separated by as little as several hundred meters. Dietary variation among and within sites can reflect differences in prey availability as well as individual specialization. We estimated species composition, density, biomass, and sizes of subtidal clams, urchins, and mussels at 13 sites in Glacier Bay and 5 sites in nearby Port Althorp, where sea otters have been present for at least 20 years. All sites were selected based on the presence of abundant clam siphons and the absence of sea otters (Glacier Bay) or abundant shell litter and the presence of sea otters (Port Althorp). Glacier Bay sites were selected to achieve a broad geographic sample of dense subtidal clam beds within

  14. Recovery from TBT pollution in English Channel environments: A problem solved?

    Science.gov (United States)

    Langston, W J; Pope, N D; Davey, M; Langston, K M; O' Hara, S C M; Gibbs, P E; Pascoe, P L

    2015-06-30

    Following recognition of effects in the 1980s, tributyltin (TBT) has been monitored at sites in the English Channel to evaluate the prognosis for biota - spanning the introduction of restrictions on TBT use on small boats and the recent phase-out on the global fleet. We describe how persistence and impact of TBT in clams Scrobicularia plana has changed during this period in Southampton Water and Poole Harbour. TBT contamination (and loss) in water, sediment and clams reflects the abundance and type of vessel activity: half-times in sediment (up to 8y in Poole, 33y in Southampton) are longest near commercial shipping. Recovery of clam populations - slowest in TBT-contaminated deposits - provides a useful biological measure of legislative efficacy in estuaries. On rocky shores, recovery from imposex in Nucella lapillus is evident at many sites but, near ports, is prolonged by shipping impac